Method and apparatus for transport block generation with ul spatial multiplexing in a wireless communication system

ABSTRACT

A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE) configured with uplink (UL) spatial multiplexing and UL skipping, the UE receives, from a base station, two UL grants for a Transmission Time Interval (TTI). The UE generates two Medium Access Control (MAC) Protocol Data Units (PDUs) for the TTI, wherein a first MAC PDU of the two MAC PDUs is able to accommodate all available data of the UE. The UE transmits the two MAC PDUs to the base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 63/022,739 filed on May 11, 2020, the entiredisclosure of which is incorporated herein in its entirety by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to a method and apparatus for transport blockgeneration with uplink (UL) spatial multiplexing in a wirelesscommunication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN). The E-UTRAN system can provide high datathroughput in order to realize the above-noted voice over IP andmultimedia services. A new radio technology for the next generation(e.g., 5G) is currently being discussed by the 3GPP standardsorganization. Accordingly, changes to the current body of 3GPP standardare currently being submitted and considered to evolve and finalize the3GPP standard.

SUMMARY

In accordance with the present disclosure, one or more devices and/ormethods are provided. In an example from the perspective of a UserEquipment (UE) configured with uplink (UL) spatial multiplexing and ULskipping, the UE receives, from a base station, two UL grants for aTransmission Time Interval (TTI). The UE generates two Medium AccessControl (MAC) Protocol Data Units (PDUs) for the TTI, wherein a firstMAC PDU of the two MAC PDUs is able to accommodate all available data ofthe UE. The UE transmits the two MAC PDUs to the base station.

In an example from the perspective of a UE configured with UL spatialmultiplexing and UL skipping, the UE receives, from a base station, twoUL grants for a TTI. The UE generates two MAC PDUs for the TTI. A firstMAC PDU of the two MAC PDUs merely comprises a first MAC Control Element(CE), for a first padding Buffer Status Report (BSR) or for a firstperiodic BSR, with zero MAC Service Data Units (SDUs). A second MAC PDUof the two MAC PDUs comprises at least one of available data of the UEor a MAC SDU. The UE transmits the two MAC PDUs to the base station.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a diagram illustrating an exemplary scenario associated withuplink physical channel processing according to one exemplaryembodiment.

FIG. 6 is a flow chart according to one exemplary embodiment.

FIG. 7 is a flow chart according to one exemplary embodiment.

FIG. 8 is a flow chart according to one exemplary embodiment.

FIG. 9 is a flow chart according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3^(rd) Generation Partnership Project (3GPP) LTE (Long Term Evolution)wireless access, 3GPP LTE-A or LTE-Advanced (Long Term EvolutionAdvanced), 3GPP2 UMB (Ultra Mobile Broadband), WiMax, 3GPP NR (NewRadio) wireless access for 5G, or some other modulation techniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including: 3GPP TS 36.321 V15.8.0,“E-UTRA, MAC protocol specification”; 3GPP TS 36.331 V15.8.0, “E-UTRA,RRC protocol specification”; 3GPP TS 36.211 V15.8.1, “E-UTRA, Physicalchannels and modulations”; 3GPP TS 36.213 V15.8.0, “E-UTRA, Physicallayer procedure”; 3GPP TS 36.212 V15.8.0, “E-UTRA, Multiplexing andchannel coding”. The standards and documents listed above are herebyexpressly incorporated by reference in their entirety.

FIG. 1 presents a multiple access wireless communication system inaccordance with one or more embodiments of the disclosure. An accessnetwork 100 (AN) includes multiple antenna groups, one including 104 and106, another including 108 and 110, and an additional including 112 and114. In FIG. 1, only two antennas are shown for each antenna group,however, more or fewer antennas may be utilized for each antenna group.Access terminal 116 (AT) is in communication with antennas 112 and 114,where antennas 112 and 114 transmit information to access terminal 116over forward link 120 and receive information from access terminal 116over reverse link 118. AT 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to AT 122 overforward link 126 and receive information from AT 122 over reverse link124. In a frequency-division duplexing (FDD) system, communication links118, 120, 124 and 126 may use different frequencies for communication.For example, forward link 120 may use a different frequency than thatused by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each may be designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragemay normally cause less interference to access terminals in neighboringcells than an access network transmitting through a single antenna toits access terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, aneNodeB (eNB), a Next Generation NodeB (gNB), or some other terminology.An access terminal (AT) may also be called user equipment (UE), awireless communication device, terminal, access terminal or some otherterminology.

FIG. 2 presents an embodiment of a transmitter system 210 (also known asthe access network) and a receiver system 250 (also known as accessterminal (AT) or user equipment (UE)) in a multiple-input andmultiple-output (MIMO) system 200. At the transmitter system 210,traffic data for a number of data streams may be provided from a datasource 212 to a transmit (TX) data processor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing orthogonal frequency-division multiplexing (OFDM) techniques. Thepilot data may typically be a known data pattern that is processed in aknown manner and may be used at the receiver system to estimate thechannel response. The multiplexed pilot and coded data for each datastream may then be modulated (i.e., symbol mapped) based on a particularmodulation scheme (e.g., binary phase shift keying (BPSK), quadraturephase shift keying (QPSK), M-ary phase shift keying (M-PSK), or M-aryquadrature amplitude modulation (M-QAM)) selected for that data streamto provide modulation symbols. The data rate, coding, and/or modulationfor each data stream may be determined by instructions performed byprocessor 230.

The modulation symbols for data streams are then provided to a TX MIMOprocessor 220, which may further process the modulation symbols (e.g.,for OFDM). TX MIMO processor 220 then provides N_(T) modulation symbolstreams to N_(T) transmitters (TMTR) 222 a through 222 t. In certainembodiments, TX MIMO processor 220 may apply beamforming weights to thesymbols of the data streams and to the antenna from which the symbol isbeing transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and/or upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t may then betransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 may be provided to a respective receiver (RCVR) 254 athrough 254 r. Each receiver 254 may condition (e.g., filters,amplifies, and downconverts) a respective received signal, digitize theconditioned signal to provide samples, and/or further process thesamples to provide a corresponding “received” symbol stream.

An RX data processor 260 then receives and/or processes the N_(R)received symbol streams from N_(R) receivers 254 based on a particularreceiver processing technique to provide N_(T) “detected” symbolstreams. The RX data processor 260 may then demodulate, deinterleave,and/or decode each detected symbol stream to recover the traffic datafor the data stream. The processing by RX data processor 260 may becomplementary to that performed by TX MIMO processor 220 and TX dataprocessor 214 at transmitter system 210.

A processor 270 may periodically determine which pre-coding matrix touse (discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message may then be processed by a TX data processor 238,which may also receive traffic data for a number of data streams from adata source 236, modulated by a modulator 280, conditioned bytransmitters 254 a through 254 r, and/or transmitted back to transmittersystem 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 may then determine which pre-coding matrix touse for determining the beamforming weights and may then process theextracted message.

FIG. 3 presents an alternative simplified functional block diagram of acommunication device according to one embodiment of the disclosedsubject matter. As shown in FIG. 3, the communication device 300 in awireless communication system can be utilized for realizing the UEs (orATs) 116 and 122 in FIG. 1 or the base station (or AN) 100 in FIG. 1,and the wireless communications system may be the LTE system or the NRsystem. The communication device 300 may include an input device 302, anoutput device 304, a control circuit 306, a central processing unit(CPU) 308, a memory 310, a program code 312, and a transceiver 314. Thecontrol circuit 306 executes the program code 312 in the memory 310through the CPU 308, thereby controlling an operation of thecommunications device 300. The communications device 300 can receivesignals input by a user through the input device 302, such as a keyboardor keypad, and can output images and sounds through the output device304, such as a monitor or speakers. The transceiver 314 is used toreceive and transmit wireless signals, delivering received signals tothe control circuit 306, and outputting signals generated by the controlcircuit 306 wirelessly. The communication device 300 in a wirelesscommunication system can also be utilized for realizing the AN 100 inFIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the disclosed subjectmatter. In this embodiment, the program code 312 includes an applicationlayer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and iscoupled to a Layer 1 portion 406. The Layer 3 portion 402 may performradio resource control. The Layer 2 portion 404 may perform linkcontrol. The Layer 1 portion 406 may perform and/or implement physicalconnections.

In LTE, a Medium Access Control (MAC) in a UE receives an uplink (UL)grant at each TTI, and/or a Hybrid Automatic Repeat Request (HARQ)entity of the UE identifies a HARQ process for each UL grant. For eachHARQ process (after identifying HARQ processes for UL grants, forexample), the UE obtains a Medium Access Control (MAC) Protocol DataUnit (PDU) for transmission from a Multiplexing and assembly entity ofthe UE. When an UL grant is available for a TTI, the UE may skip the ULgrant (and/or may not generate a MAC PDU), such as called uplinkskipping, under some conditions, e.g., if there is no uplink data (e.g.,MAC Service Data Unit (SDU)) and/or if the MAC PDU merely comprises aMAC CE (e.g., a MAC CE, for padding BSR or periodic BSR, with zero MACSDUs). Details of UL transmission procedure are provided in 3GPP TS36.321 V15.8.0. Portions of 3GPP TS 36.321 V15.8.0 are quoted below:

5.4 UL-SCH Data Transfer 5.4.1 UL Grant Reception

In order to transmit on the UL-SCH the MAC entity must have a validuplink grant (except for non-adaptive HARQ retransmissions) which it mayreceive dynamically on the PDCCH or in a Random Access Response or whichmay be configured semi-persistently or preallocated by RRC. To performrequested transmissions, the MAC layer receives HARQ information fromlower layers. When the physical layer is configured for uplink spatialmultiplexing, the MAC layer can receive up to two grants (one per HARQprocess) for the same TTI from lower layers.

If the MAC entity has a C-RNTI, a Semi-Persistent Scheduling C-RNTI, aUL Semi-Persistent Scheduling V-RNTI, a AUL C-RNTI, or a TemporaryC-RNTI, the MAC entity shall for each TTI and for each Serving Cellbelonging to a TAG that has a running timeAlignmentTimer and for eachgrant received for this TTI and for each SPS configuration that isindicated by the PDCCH addressed to UL Semi-Persistent SchedulingV-RNTI:

-   -   if an uplink grant for this TTI and this Serving Cell has been        received on the PDCCH for the MAC entity's C-RNTI or Temporary        C-RNTI; or    -   if an uplink grant for this TTI has been received in a Random        Access Response:    -   < . . . >        -   deliver the uplink grant and the associated HARQ information            to the HARQ entity for this TTI.    -   < . . . >

5.4.2 HARQ Operation 5.4.2.1 HARQ Entity

There is one HARQ entity at the MAC entity for each Serving Cell withconfigured uplink,

< . . . >

When the physical layer is configured for uplink spatial multiplexing,as specified in TS 36.213 [2], there are two HARQ processes associatedwith a given TTI. Otherwise there is one HARQ process associated with agiven TTI.

At a given TTI, if an uplink grant is indicated for the TTI, the HARQentity identifies the HARQ process(es) for which a transmission shouldtake place. It also routes the received HARQ feedback (ACK/NACKinformation), MCS and resource, relayed by the physical layer, to theappropriate HARQ process(es).

< . . . >

For each TTI, the HARQ entity shall:

-   -   identify the HARQ process(es) associated with this TTI, and for        each identified HARQ process:        -   if an uplink grant has been indicated for this process and            this TTI:            -   < . . . >                -   obtain the MAC PDU to transmit from the                    “Multiplexing and assembly” entity, if any;                -   if a MAC PDU to transmit has been obtained:                -   deliver the MAC PDU and the uplink grant and the                    HARQ information to the identified HARQ process;                -   instruct the identified HARQ process to trigger a                    new transmission.                -   else:                -   flush the HARQ buffer of the identified HARQ                    process.

5.4.2.2 HARQ Process

Each HARQ process is associated with a HARQ buffer.

< . . . >

If the HARQ entity requests a new transmission, the HARQ process shall:

< . . . >

-   -   store the MAC PDU in the associated HARQ buffer;    -   store the uplink grant received from the HARQ entity;    -   generate a transmission as described below.

< . . . >

To generate a transmission, the HARQ process shall:

-   -   if the MAC PDU was obtained from the Msg3 buffer; or    -   if Sidelink Discovery Gaps for Transmission are not configured        by upper layers, and there is no measurement gap at the time of        the transmission and, in case of retransmission, the        retransmission does not collide with a transmission for a MAC        PDU obtained from the Msg3 buffer in this TTI; or        -   < . . . >—instruct the physical layer to generate a            transmission according to the stored uplink grant with the            redundancy version corresponding to the CURRENT_IRV value;        -   < . . . >

5.4.3 Multiplexing and Assembly 5.4.3.1 Logical Channel Prioritization

The Logical Channel Prioritization procedure is applied when a newtransmission is performed.

< . . . > The MAC entity shall perform the following Logical ChannelPrioritization procedure when a new transmission is performed on an ULgrant with a certain TTI length:

-   -   The MAC entity shall allocate resources to the logical channels        that are allowed to transmit using the TTI length of the grant,        in the following steps:        -   Step 1: All the allowed logical channels with Bj>0 are            allocated resources in a decreasing priority order. If the            PBR of a logical channel is set to “infinity”, the MAC            entity shall allocate resources for all the data that is            available for transmission on the logical channel before            meeting the PBR of the lower priority logical channel(s);        -   Step 2: the MAC entity shall decrement Bj by the total size            of MAC SDUs served to logical channel j in Step 1;    -   NOTE 1: The value of Bj can be negative.        -   Step 3: if any resources remain, all the allowed logical            channels are served in a strict decreasing priority order            (regardless of the value of Bj) until either the data for            that logical channel or the UL grant is exhausted, whichever            comes first. Logical channels configured with equal priority            should be served equally.        -   The UE shall also follow the rules below during the            scheduling procedures above:        -   the UE should not segment an RLC SDU (or partially            transmitted SDU or retransmitted RLC PDU) if the whole SDU            (or partially transmitted SDU or retransmitted RLC PDU) fits            into the remaining resources of the associated MAC entity;        -   if the UE segments an RLC SDU from the logical channel, it            shall maximize the size of the segment to fill the grant of            the associated MAC entity as much as possible;        -   the UE should maximise the transmission of data.        -   if the MAC entity is given an UL grant size that is equal to            or larger than 4 bytes while having data available for            transmission, the MAC entity shall not transmit only padding            BSR and/or padding (unless the UL grant size is less than 7            bytes and an AMD PDU segment needs to be transmitted);

< . . . >

If the MAC PDU includes only the MAC CE for padding BSR or periodic BSRwith zero MAC SDUs and there is no aperiodic CSI requested for this TTI,as specified in TS 36.213 [2], the MAC entity shall not generate a MACPDU for the HARQ entity in the following cases:

-   -   in case the MAC entity is configured with skip UplinkTxDynamic        and the grant indicated to the HARQ entity was addressed to a        C-RNTI; or    -   in case the MAC entity is configured with skipUplinkTxSPS and        the grant indicated to the HARQ entity is a configured uplink        grant activated by the MAC entity's Semi-Persistent Scheduling        C-RNTI or by the MAC entity's UL Semi-Persistent Scheduling        V-RNTI; or    -   in case the grant indicated to the HARQ entity is a configured        uplink grant activated by the MAC entity's AUL C-RNTI.

For the Logical Channel Prioritization procedure, the MAC entity shalltake into account the following relative priority in decreasing order:

-   -   MAC control element for C-RNTI or data from UL-CCCH;    -   MAC control element for DPR;    -   MAC control element for SPS confirmation;    -   MAC control element for AUL confirmation;    -   MAC control element for BSR, with exception of BSR included for        padding;    -   MAC control element for PHR, Extended PHR, or Dual Connectivity        PHR;    -   MAC control element for Sidelink BSR, with exception of Sidelink        BSR included for padding;    -   data from any Logical Channel, except data from UL-CCCH;    -   MAC control element for Recommended bit rate query;    -   MAC control element for BSR included for padding;    -   MAC control element for Sidelink BSR included for padding.    -   NOTE 2: When the MAC entity is requested to transmit multiple        MAC PDUs in one TTI, steps 1 to 3 and the associated rules may        be applied either to each grant independently or to the sum of        the capacities of the grants. Also the order in which the grants        are processed is left up to UE implementation. It is up to the        UE implementation to decide in which MAC PDU a MAC control        element is included when MAC entity is requested to transmit        multiple MAC PDUs in one TTI. When the UE is requested to        generate MAC PDU(s) in two MAC entities in one TTI, it is up to        UE implementation in which order the grants are processed.

5.4.3.2 Multiplexing of MAC Control Elements and MAC SDUs

The MAC entity shall multiplex MAC control elements and MAC SDUs in aMAC PDU according to clauses 5.4.3.1 and 6.1.2.

Configurations of uplink skipping may be provided by Radio ResourceControl (RRC), such as specified in 3GPP TS 36.331 V15.8.0. Portions of3GPP TS 36.331 V15.8.0 are quoted below:

MAC-MainConfig

The IE MAC-MainConfig is used to specify the MAC main configuration forsignalling and data radio bearers. All MAC main configuration parameterscan be configured independently per Cell Group (i.e. MCG or SCG), unlessexplicitly specified otherwise.

MAC-MainConfig Information Element

ASN1START MAC-MainConfig ::= SEQUENCE {  <. . .>  [[ skipUplinkTx-r14 CHOICE {   release   NULL,   setup  SEQUENCE {    skipUplinkTxSPS-r14   ENUMERATED {true}  OPTIONAL, -- Need OR    skipUplinkTxDynamic-r14   ENUMERATED {true}  OPTIONAL -- Need OR    }   }     OPTIONAL, -- NeedON  <. . .> } <. . .>

skipUplinkTxDynamic If configured, the UE skips UL transmissions for anuplink grant other than a configured uplink grant if no data isavailable for transmission in the UE buffer as described in IS 36.321[6]. skipUplinkTxSPS If configured, the UE skips UL transmissions for aconfigured uplink grant if no data is available for transmission in theUE buffer as described in TS 36.321 [6]. E-UTRAN always configuresskipUplinkTxSPS when there is at least one SPS configuration withsemiPersistSchedIntervalUL shorter than sf10 or when at least oneSPS-ConfigUL-STTI is configured for the cell group.

UL spatial multiplexing is introduced to boost UL data rate. Multiplelayers with different data may be transmitted on a same time/frequencyresource (e.g., one or more resource elements and/or one or moreresource blocks), e.g., by mapping the multiple layers to multipleantenna elements or multiple antenna ports. In some examples, with ULspatial multiplexing, there may be up to four layers and/or up to twotransport blocks (codewords) supported for UL transmission in aTransmission Time Interval (TTI), e.g., a subframe. A UE may be able toutilize UL spatial multiplexing when a (UL, for example) transmissionmode, e.g., transmission mode 2 (e.g., UL transmission mode 2), isconfigured. Physical Downlink Control Channel (PDCCH) and/or DownlinkControl Information (DCI) may be used to enable or disable spatialmultiplexing. For example, DCI format associated with single antennaport (e.g., DCI format 0) may be used to disable spatial multiplexing.When a UE receives a DCI format associated with single antenna port, theUE may perform a corresponding Physical Uplink Shared Channel (PUSCH)transmission without spatial multiplexing (with a single antenna port,for example). PUSCH transmission without spatial multiplexing comprisesa single transport block (and/or a single codeword). DCI formatassociated with spatial multiplexing (e.g., DCI format 4) may be used toenable spatial multiplexing. When a UE receives a DCI format associatedwith spatial multiplexing, the UE may perform corresponding PUSCHtransmission with spatial multiplexing (with multiple antenna ports, forexample). PUSCH transmission with spatial multiplexing may comprise asingle transport block (e.g., a single codeword) or two transport blocks(e.g., two codewords). Information carried on a DCI format associatedwith spatial multiplexing may be used to disable a transport block ofthe corresponding PUSCH transmission. Information carried on a DCIformat associated with spatial multiplexing may be used to inform the UEthat the corresponding PUSCH transmission comprises a single transportblock (e.g., one transport block enabled and one transport blockdisabled) or two transport blocks (e.g., both transport blocks enabled).For example, resource block assignment field and modulation codingscheme field associated with a transport block in a DCI formatassociated with spatial multiplexing may be used to inform the UEwhether the transport block is enabled or disabled (e.g., a transportbock is disabled if either the combination of I_(MCS)=0 and N_(PRB)>1 orthe combination of I_(MCS)=28 and N_(PRB)=1 is signaled). Detailsrelated to spatial multiplexing are provided in 3GPP TS 36.211 V15.8.1,3GPP TS 36.213 V15.8.0, and 3GPP TS 36.212 V15.8.0.

Notably, Figure 5.3-1 of Section 5.3 of 3GPP TS 36.211 V15.8.1, entitled“Overview of uplink physical channel processing”, is reproduced hereinas FIG. 5. Portions of 3GPP TS 36.211 V15.8.1 are quoted below:

5.3 Physical Uplink Shared Channel

The baseband signal representing the physical uplink shared channel isdefined in terms of the following steps:

-   -   scrambling    -   modulation of scrambled bits to generate complex-valued symbols    -   mapping of the complex-valued modulation symbols onto one or        several transmission layers    -   transform precoding to generate complex-valued symbols    -   precoding of the complex-valued symbols    -   mapping of precoded complex-valued symbols to resource elements    -   generation of complex-valued time-domain SC-FDMA signal for each        antenna port

Figure 5.3-1: Overview of Uplink Physical Channel Processing

< . . . >

5.3.2A.2 Layer Mapping for Spatial Multiplexing

For spatial multiplexing, the layer mapping shall be done according toTable 5.3.2A.2-1. The number of layers ν is less than or equal to thenumber of antenna ports P used for transmission of the physical uplinkshared channel.

The case of a single codeword mapped to multiple layers is onlyapplicable when the number of antenna ports used for PUSCH is four,except for slot-PUSCH and subslot-PUSCH transmission where a singlecodeword is used irrespective of the number of layers.

TABLE 5.3.2A.2-1 Codeword-to-layer mapping for spatial multiplexingNumber Number of Codeword-to-layer mapping of layers codewords i = 0, 1,. . . , M_(symb) ^(layer) − 1 1 1 x⁽⁰⁾ (i) = d⁽⁰⁾ (i) M_(symb) ^(layer)= M_(symb) ⁽⁰⁾ 2 1 x⁽⁰⁾ (i) = d⁽⁰⁾ (2i) M_(symb) ^(layer) = M_(symb)⁽⁰⁾/2 x⁽¹⁾ (i) = d⁽⁰⁾ (2i + 1) 2 2 x⁽⁰⁾ (i) = d⁽⁰⁾ (i) M_(symb) ^(layer)= M_(symb) ⁽⁰⁾ = x⁽¹⁾ (i) = d⁽¹⁾ (i) M_(symb) ⁽¹⁾ 3 2 x⁽⁰⁾ (i) = d⁽⁰⁾(i) M_(symb) ^(layer) = M_(symb) ⁽⁰⁾ = x⁽¹⁾ (i) = d⁽¹⁾ (2i) M_(symb)⁽¹⁾/2 x⁽²⁾ (i) = d⁽¹⁾ (2i + 1) 4 2 x⁽⁰⁾ (i) = d⁽⁰⁾ (2i) M_(symb)^(layer) = M_(symb) ⁽⁰⁾/2 = x⁽¹⁾ (i) = d⁽⁰⁾ (2i + 1) M_(symb) ⁽¹⁾/2 x⁽²⁾(i) = d⁽¹⁾ (2i) x⁽³⁾ (i) = d⁽¹⁾ (2i + 1)  4¹  1¹ x⁽⁰⁾ (i) = d⁽⁰⁾ (4i)M_(symb) ^(layer) = M_(symb) ⁽⁰⁾/4 x⁽¹⁾ (i) = d⁽⁰⁾ (4i + 1) x⁽²⁾ (i) =d⁽⁰⁾ (4i + 2) x⁽³⁾ (i) = d⁽⁰⁾ (4i + 3) NOTE 1: Only used for slot- PUSCHand subslot-PUSCH

< . . . >

5.3.3A.2 Precoding for Spatial Multiplexing

Precoding for spatial multiplexing is only used in combination withlayer mapping for spatial multiplexing as described in clause 5.3.2A.2.Spatial multiplexing supports P=2 or P=4 antenna ports where the set ofantenna ports used for spatial multiplexing is p∈{20,21} andp∈{40,41,42,43}, respectively.

Precoding for spatial multiplexing is defined by

$\begin{matrix}{\begin{bmatrix}{z^{(0)}(i)} \\\vdots \\{z^{({P­1})}(i)}\end{bmatrix} = {W\begin{bmatrix}{y^{(0)}(i)} \\\vdots \\{y^{({v­1})}(i)}\end{bmatrix}}} & \;\end{matrix}$

where i=0, 1, . . . , M_(symb) ^(ap)−1, M_(symb) ^(ap)=M_(symb)^(layer).

The precoding matrix w of size p×ν is given by one of the entries inTable 5.3.3A.2-1 for P=2 and by Tables 5.3.3A.2-2 through 5.3.3A.2-5 forP=4 where the entries in each row are ordered from left to right inincreasing order of codebook indices.

TABLE 5.3.3A.2-1 Codebook for transmission on antenna ports {20, 21}Number of layers Codebook index ν = 1 ν = 2 0$\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\1\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 0 \\0 & 1\end{bmatrix}$ 1 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- 1}\end{bmatrix}$ — 2 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\j\end{bmatrix}$ — 3 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- j}\end{bmatrix}$ — 4 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\0\end{bmatrix}$ — 5 $\frac{1}{\sqrt{2}}\begin{bmatrix}0 \\1\end{bmatrix}$ —

TABLE 5.3.3A.2-2 Codebook for transmission on antenna ports {40, 41, 42,43} with ν = 1 Codebook index Number of layers ν = 1  0-7$\frac{1}{2}\begin{bmatrix}1 \\1 \\1 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\j \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- 1} \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\1 \\{- j} \\{- j}\end{bmatrix}$  8-15 $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\1 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\j \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- 1} \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- 1} \\{- j} \\j\end{bmatrix}$ 16-23 $\frac{1}{2}\begin{bmatrix}1 \\0 \\1 \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- 1} \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\j \\0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\0 \\{- j} \\0\end{bmatrix}$  0-7 $\frac{1}{2}\begin{bmatrix}1 \\j \\1 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\j \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- 1} \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\j \\{- j} \\{- 1}\end{bmatrix}$  8-15 $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\1 \\{- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\j \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- 1} \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 \\{- j} \\{- j} \\1\end{bmatrix}$ 16-23 $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 \\1 \\0 \\{- j}\end{bmatrix}$

TABLE 5.3.3A.2-3 Codebook for transmission on antenna ports {40, 41, 42,43} with ν = 2 Codebook index Number of layers ν = 2  0-3$\frac{1}{2}\begin{bmatrix}1 & 0 \\1 & 0 \\0 & 1 \\0 & {- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\1 & 0 \\0 & 1 \\0 & j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\{- j} & 0 \\0 & 1 \\0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\{- j} & 0 \\0 & 1 \\0 & {- 1}\end{bmatrix}$  4-7 $\frac{1}{2}\begin{bmatrix}1 & 0 \\{- 1} & 0 \\0 & 1 \\0 & {- j}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\{- 1} & 0 \\0 & 1 \\0 & j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\j & 0 \\0 & 1 \\0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\j & 0 \\0 & 1 \\0 & {- 1}\end{bmatrix}$  8-11 $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\1 & 0 \\0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\1 & 0 \\0 & {- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\{- 1} & 0 \\0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\{- 1} & 0 \\0 & {- 1}\end{bmatrix}$ 12-15 $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\0 & 1 \\1 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\0 & {- 1} \\1 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\0 & 1 \\{- 1} & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 \\0 & 1 \\0 & {- 1} \\{- 1} & 0\end{bmatrix}$

TABLE 5.3.3A.2-4 Codebook for transmission on antenna ports {40, 41, 42,43} with ν = 3 Codebook index Number of layers ν = 3 0-3$\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\{- 1} & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\1 & 0 & 0 \\0 & 0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\{- 1} & 0 & 0 \\0 & 0 & 1\end{bmatrix}$ 4-7 $\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1 \\1 & 0 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1 \\{- 1} & 0 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\1 & 0 & 0 \\1 & 0 & 0 \\0 & 0 & 1\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\1 & 0 & 0 \\{- 1} & 0 & 0 \\0 & 0 & 1\end{bmatrix}$ 8-11 $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\1 & 0 & 0 \\0 & 0 & 1 \\1 & 0 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\1 & 0 & 0 \\0 & 0 & 1 \\{- 1} & 0 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\0 & 0 & 1 \\1 & 0 & 0 \\1 & 0 & 0\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}0 & 1 & 0 \\0 & 0 & 1 \\1 & 0 & 0 \\{- 1} & 0 & 0\end{bmatrix}$

TABLE 5.3.3A.2-5 Codebook for transmission on antenna ports {40, 41, 42,43} with ν = 4 Codebook index Number of layers ν = 4 0$\frac{1}{2}\begin{bmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 1 & 0 \\0 & 0 & 0 & 1\end{bmatrix}$

Portions of 3GPP TS 36.213 V15.8.0 are quoted below:

8 Physical Uplink Shared Channel Related Procedures

< . . . >

For a non-BL/CE UE, and for FDD and transmission mode 1 and a cell thatis not a LAA SCell, there shall be 16 uplink HARQ processes per servingcell configured with higher layer parameter ul-STTI-Length, otherwise 8uplink HARQ processes per serving cell for non-subframe bundlingoperation, i.e. normal HARQ operation

< . . . > For a non-BL/CE UE, and for FDD and transmission mode 2configured for subframe-PUSCH and a cell that is not a LAA SCell, thereshall be 32 uplink HARQ processes per serving cell configured withhigher layer parameters ul-STTI-Length and shortProcessingTime,otherwise 16 uplink HARQ processes per serving cell for non-subframebundling operation and there are two HARQ processes associated with agiven subframe for subframe-PUSCH as described in [8].

< . . . >

For a serving cell that is not a LAA SCell, and for FDD and normal HARQoperation, the UE shall upon detection on a given serving cell of a

-   -   PDCCH/EPDCCH with DCI format 0/4 and/or a PHICH transmission in        subframe n intended for the UE, perform a corresponding PUSCH        transmission in subframe n+k_(p) according to the PDCCH/EPDCCH        and PHICH information where k_(p)=3 if the UE is configured with        higher layer parameter shortProcessingTime and the corresponding        PDCCH with CRC scrambled by C-RNTI is in the UE-specific search        space, k_(p)=4 otherwise.    -   < . . . >

if a transport block corresponding to the HARQ process of the PUSCHtransmission is generated as described in [8].

< . . . >

If a UE is configured by higher layers to decode PDCCHs with the CRCscrambled by the C-RNTI, the UE shall decode the PDCCH according to thecombination defined in Table 8-3 and transmit the corresponding PUSCH ifa transport block corresponding to the HARQ process of the PUSCHtransmission is generated as described in [8].

< . . . >

Transmission mode 1 is the default uplink transmission mode for a UEuntil the UE is assigned an uplink transmission mode by higher layersignalling.

When a UE configured in transmission mode 2 receives a DCI Format0/0A/0B/0C uplink scheduling grant, it shall assume that the PUSCHtransmission is associated with transport block 1 and that transportblock 2 is disabled.

TABLE 8-3 PDCCH and PUSCH configured by C-RNTI Transmission scheme ofPUSCH Transmission corresponding mode DCI format Search Space to PDCCHMode 1 DCI format 0 Common and Single-antenna port, UE specific port 10(see Subclause by C-RNTI 8.0.1) DCI format 0A or UE specificSingle-antenna port, 0B or 0C or 7-0A by C-RNTI port 10 (see Subclause8.0.1) Mode 2 DCI format 0 Common and Single-antenna port, UE specificport 10 (see Subclause by C-RNTI 8.0.1) DCI format 0A or UE specificSingle-antenna port, 0B or 0C by C-RNTI port 10 (see Subclause 8.0.1)DCI format 4 or 4A UE specific Closed-loop spatial or 4B or 7-0B byC-RNTI multiplexing (see Subclause 8.0.2)

8.6.2 Transport Block Size Determination

For a non-BL/CE UE and for 0≤I_(MCS)≤28, the UE shall first determinethe TBS index (I_(TBS)) using I_(MCS) except if the transport block isdisabled in DCI format 4/4A/4B as specified below.

< . . . >

In DCI format 4 a transport block is disabled if either the combinationof I_(MCS)=0 and N_(PRB)>1 or the combination of I_(MCS)=28 andN_(PRB)=1 is signalled, otherwise the transport block is enabled.

Portions of 3GPP TS 36.212 V15.8.0 are quoted below:

5.3.3.1.8 Format 4

DCI format 4 is used for the scheduling of PUSCH in one UL cell withmulti-antenna port transmission mode,

The following information is transmitted by means of the DCI format 4:

-   -   Carrier indicator—0 or 3 bits. The field is present according to        the definitions in [3].

${{{Resource}\mspace{14mu}{block}\mspace{14mu}{assignment}} - {{\max\left( {\left\lceil {\log_{2}\left( {{N_{RB}^{UL}\left( {N_{RB}^{UL} + 1} \right)}/2} \right)} \right\rceil,\left\lceil {\log_{2}\left( \begin{pmatrix}\left\lceil {{N_{RB}^{UL}/P} + 1} \right\rceil \\4\end{pmatrix} \right)} \right\rceil} \right)}{bits}}},$

where

-   -   P is the UL RBG size as defined in subclause 8.1.2 of [3]    -   < . . . >

In addition, for transport block 1:

-   -   Modulation and coding scheme and redundancy version—5 bits as        defined in subclause 8.6 of [3]    -   New data indicator—1 bit

In addition, for transport block 2:

-   -   Modulation and coding scheme and redundancy version—5 bits as        defined in subclause 8.6 of [3]    -   New data indicator—1 bit

Precoding information and number of layers: number of bits as specifiedin Table 5.3.3.1.8-1. Bit field as shown in Table 5.3.3.1.8-2 and Table5.3.3.1.8-3.

< . . . >

TABLE 5.3.3.1.8-1 Number of bits for precoding information Number ofantenna Number of bits for precoding ports at UE information 2 3 4 6

TABLE 5.3.3.1.8-2 Content of precoding information field for 2 antennaports One codeword: Two codewords: Codeword 0 enabled Codeword 0 enabledCodeword 1 disabled Codeword 1 enabled Bit field Bit field mapped mappedto index Message to index Message 0 1 layer: TPMI = 0 0 2 layers: TPMI =0 1 1 layer: TPMI = 1 1-7 reserved 2 1 layer: TPMI = 2 . . . . . . 5 1layer: TPMI = 5 6-7 reserved

TABLE 5.3.3.1.8-3 Content of precoding information field for 4 antennaports One codeword: Two codewords: Codeword 0 enabled Codeword 0 enabledCodeword 1 disabled Codeword 1 enabled Bit field Bit field mapped mappedto index Message to index Message 0 1 layer: TPMI = 0 0 2 layers: TPMI =0 1 1 layer: TPMI = 1 1 2 layers: TPMI = 1 . . . . . . . . . . . . 23  1layer: TPMI = 23 15  2 layers: TPMI = 15 24 2 layers: TPMI = 0  16 3layers: TPMI = 0 25 2 layers: TPMI = 1  17 3 layers: TPMI = 1 . . . . .. . . . . . . 39  2 layers: TPMI = 15  27  3 layers: TPMI = 11 40-63reserved 28 4 layers: TPMI = 0 29-63 Reserved

In LTE, a Medium Access Control (MAC) of a UE can receive an uplink (UL)grant dynamically on a Physical Downlink Control Channel (PDCCH).Alternatively and/or additionally, the MAC of the UE may receive an ULgrant in a Random Access Response. Alternatively and/or additionally, anUL grant may be configured (for the MAC and/or the UE, for example)semi-persistently. A Hybrid Automatic Repeat Request (HARQ) entity (inthe MAC, for example) may maintain HARQ processes (e.g., multipleparallel HARQ process, such as amounting to a first number of HARQprocesses). The HARQ entity may identify HARQ processes (e.g., the HARQprocesses maintained by the HARQ entity) associated with UL grants forTransmission Time Intervals (TTIs). For example, each HARQ process ofthe identified HARQ processes may be associated with a UL grant (of theUL grants, for example) for a TTI (of the TTIs, for example). In anexample, each UL grant (for a TTI of the TTIs, for example) of the ULgrants may be associated with a HARQ process of the identified HARQprocesses. The HARQ entity may obtain a MAC Protocol Data Unit (PDU)from a Msg3 buffer and/or a Multiplexing and assembly entity for a HARQprocess (e.g., an identified HARQ process of the identified HARQprocesses). If the Multiplexing and assembly entity does not generate aMAC PDU (such as according to a Logical Channel Prioritization (LCP)procedure), the HARQ entity may flush a related HARQ process buffer(associated with the identified HARQ process, for example). A MAC PDUmay not be generated if there is no available data for transmission,when skipUplinkTxDynamic is configured for dynamic UL grant (addressedto a Cell Radio Network Temporary Identifier (C-RNTI), for example)and/or skipUplinkTxSPS is configured for configured UL grant (addressedto a Semi-Persistent Scheduling C-RNTI, for example). UL skipping (e.g.,skipUplinkTxDynamic and/or skipUplinkTxSPS) is configured by the RRC.

When the UE is configured for UL spatial multiplexing, the MAC mayreceive two dynamic UL grants for a TTI from lower layer, e.g., physicallayer (PHY). The HARQ entity may identify two HARQ processes (or adifferent number of HARQ processes) for the TTI. The HARQ entity mayobtain a MAC PDU for each of the two HARQ processes. The MAC maytransmit (after obtaining two MAC PDUs for the two HARQ processes, forexample) the two MAC PDUs as transport blocks (TBs) to the PHY for theTTI. However, if there is not enough available data for the TTI andskipUplinkTxDynamic is configured in the UE (e.g., if one UL grant ofthe two dynamic UL grants accommodates available data and there ismerely padding left for another UL grant of the two dynamic UL grants),the Multiplexing and assembly entity may generate only one MAC PDU suchas due to the UE not generating a MAC PDU comprising merely padding whenskipUplinkTxDynamic is configured (and/or due to there being noaperiodic Channel State Information (CSI) requested for the TTI). Forexample, UL skipping for the two dynamic UL grants may be examinedand/or implemented separately. The MAC may transmit only one transportblock to the PHY although the MAC receives two UL grants with UL spatialmultiplexing. UL skipping may be applied for one UL grant while ULskipping is not applied to another UL grant. The PHY may expect twotransport blocks (or two codewords) when there are two dynamic UL grantsfor a TTI. For example, 4 layer UL transmission may be indicated (withtwo transport blocks enabled, for example) for the TTI and/or the PHYmay expect there to be two transport blocks generated with eachtransport block of the two transport blocks mapped to two layers. ThePHY may be unable to generate a 4 layer transmission properly withmerely one transport block (e.g., with a precoder for spatialmultiplexing

$\left. {\frac{1}{2}\begin{bmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 1 & 0 \\0 & 0 & 0 & 1\end{bmatrix}} \right).$

To solve one or more of the aforementioned issues (e.g., at least one ofan issue that a MAC of a UE transmits merely one transport block to aPHY even though the MAC receives two UL grants with UL spatialmultiplexing, where the PHY may expect two transport blocks, an issuethat the PHY may be unable to generate a 4 layer transmission properlywith merely one transport block, etc.), it may not be allowed (for anetwork, for example) to provide a configuration (and/or anyconfiguration) that causes a UE to be configured with (and/or toimplement) UL spatial multiplexing and UL transmission skipping(simultaneously and/or concurrently, for example). Alternatively and/oradditionally, it may be allowed (for the network, for example) toprovide a configuration (and/or any configuration) that causes a UE tobe configured with (and/or to implement) UL spatial multiplexing withoutUL transmission skipping. Alternatively and/or additionally, it may beallowed (for the network, for example) to provide a configuration(and/or any configuration) that causes a UE to be configured with(and/or to implement) UL transmission skipping without UL spatialmultiplexing.

For example, the network may not be allowed and/or configured toconfigure the UE to simultaneously and/or concurrently execute and/orenable UL spatial multiplexing and UL transmission skipping. In someexamples, the network may be allowed and/or configured to configure theUE to execute and/or enable UL spatial multiplexing during a time atwhich the UE does not execute and/or enable UL transmission skipping(e.g., the network may provide the UE with a configuration indicative ofexecuting and/or enabling UL spatial multiplexing at a time and/or notexecuting and/or enabling UL transmission skipping at the time).Alternatively and/or additionally, the network may be allowed and/orconfigured to configure the UE to execute and/or enable UL transmissionskipping during a time at which the UE does not execute and/or enable ULspatial multiplexing (e.g., the network may provide the UE with aconfiguration indicative of executing and/or enabling UL transmissionskipping at a time and/or not executing and/or enabling UL spatialmultiplexing at the time).

In some examples, if a UE is configured for UL spatial multiplexing(e.g., configured in UL transmission mode 2), the NW may not provide theUE with a configuration (and/or any configuration) having a firstparameter set to true that indicates UL skipping (e.g., skipUplinkTxDynamic) in RRC configuration. For example, the network may notconfigure the UE with a first parameter, indicative of UL skipping(e.g., skipUplinkTxDynamic), when the UL spatial multiplexing isconfigured for the UE (and/or when the UL spatial multiplexing isconfigured for the UE, the network may not set the first parameter to avalue indicative of UL skipping being enabled and/or true). For example,the network may configure the UE with a first parameter, indicative ofnot configuring and/or executing UL skipping (e.g., skipUplinkTxDynamic), when the UL spatial multiplexing is configured for theUE (and/or the network may set the first parameter to a value indicativeof UL skipping being false when the UL spatial multiplexing isconfigured for the UE).

In some examples, if a first parameter to indicate UL skipping (e.g.,skip UplinkTxDynamic) in RRC configuration is set to true, the networkmay not provide a configuration (and/or any configuration) such that theUE is configured for UL spatial multiplexing (e.g., configured in ULtransmission mode 2). For example, the network may not configure ULspatial multiplexing if a first parameter to indicate UL skipping (e.g.,skip UplinkTxDynamic) is configured for the UE. Alternatively and/oradditionally, the network may not configure the UL spatial multiplexingif the value of a first parameter to indicate UL skipping (e.g., skipUplinkTxDynamic) is configured as true for the UE.

In an example, the network may configure UL spatial multiplexing and maynot configure a first parameter to indicate UL skipping (e.g., skipUplinkTxDynamic) to the UE. The UE may receive two UL grants for a TTI.Because a first parameter to indicate UL skipping (e.g., skipUplinkTxDynamic) is not configured for the UE (and/or because the UE isnot configured with UL skipping when the UE receives the two UL grants),the UE may generate two MAC PDUs even though the UE may have less than athreshold amount of available data for the TTI. In some examples, thethreshold amount of available data may correspond to an amount ofavailable data accommodated by an UL grant of the two UL grants. Forexample, an amount of available data of the UE being less than thethreshold amount of available data may indicate that the UE does nothave enough available data for the TTI and/or the two UL grants (e.g.,merely one UL grant of the two UL grants may accommodate all theavailable data). One and/or both of the two MAC PDUs associated with theTTI may merely comprise padding Buffer Status Report (BSR), and/orperiodic BSR with zero MAC Service Data Units (SDUs).

In some examples, the network may configure the UE with UL spatialmultiplexing and UL skipping. In some examples, the network is notallowed (and/or is not configured) to indicate to and/or instruct (via aDCI, for example) the UE to perform UL transmission with two transportblocks if (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping (and/or if and/or when the UE is configuredwith UL spatial multiplexing and UL skipping). In some examples, thenetwork is not allowed (and/or is not configured) to indicate, to the UE(via a DCI, for example), two UL grants for a first TTI if (and/or when)the network configures the UE with UL spatial multiplexing and ULskipping (and/or if and/or when the UE is configured with UL spatialmultiplexing and UL skipping). In some examples, the network is notallowed (and/or is not configured) to indicate to and/or instruct (via aDCI, for example) the UE to enable both transport blocks of twotransport blocks if (and/or when) the network configures the UE with ULspatial multiplexing and UL skipping (and/or if and/or when the UE isconfigured with UL spatial multiplexing and UL skipping). In someexamples, the network is not allowed (and/or is not configured) toindicate (via a DCI format associated with spatial multiplexing, forexample), to the UE, a first combination of I_(MCS)=0 and N_(PRB)>1 nora second combination of I_(MCS)=28 and N_(PRB)=1, for two transportblocks (and/or for both transport blocks of the two transport blocks) if(and/or when) the network configures the UE with UL spatial multiplexingand UL skipping (and/or if and/or when the UE is configured with ULspatial multiplexing and UL skipping). In some examples, I_(MCS), asused herein, may be indicative of a modulation and coding scheme to beused for an UL transmission. In some examples, N_(PRB), as used herein,may be indicative of a number of resource blocks to be used for an ULtransmission. In some examples, the DCI format associated with spatialmultiplexing indicates that a transport block of the two transportblocks is disabled. In some examples, the network shall indicate toand/or instruct (via a DCI, for example) the UE to perform ULtransmission with a single transport block (e.g., only one transportblock) if (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping (and/or if and/or when the UE is configuredwith UL spatial multiplexing and UL skipping). In some examples, thenetwork shall indicate to and/or instruct (via a DCI, for example) theUE to enable a single transport block if (and/or when) the networkconfigures the UE with UL spatial multiplexing and UL skipping (and/orif and/or when the UE is configured with UL spatial multiplexing and ULskipping). In some examples, the network shall indicate to and/orinstruct (via a DCI, for example) the UE to disable the one transportblock if (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping (and/or if and/or when the UE is configuredwith UL spatial multiplexing and UL skipping). In some examples, thenetwork shall indicate (via a DCI format associated with spatialmultiplexing, for example), to the UE, either a first combination ofI_(MCS)=0 and N_(PRB)>1 or a second combination of I_(MCS)=28 andN_(PRB)=1 for a transport block if (and/or when) the network configuresthe UE with UL spatial multiplexing and UL skipping (and/or if and/orwhen the UE is configured with UL spatial multiplexing and UL skipping).In some examples, the network shall schedule the UE with DCI format 0 orschedule the UE with a DCI format associated with spatial multiplexingif (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping (and/or if and/or when the UE is configuredwith UL spatial multiplexing and UL skipping), wherein either a firstcombination of I_(MCS)=0 and N_(PRB)>1 or a second combination ofI_(MCS)=28 and N_(PRB)=1 for a transport block is signaled and/orindicated in the DCI format associated with spatial multiplexing.

In some examples, the network may configure the UE with UL spatialmultiplexing and UL skipping. In some examples, the network is notallowed (and/or is not configured) enable spatial multiplexing for theUE with DCI if (and/or when) the network configures the UE with ULspatial multiplexing and UL skipping (and/or if and/or when the UE isconfigured with UL spatial multiplexing and UL skipping). In someexamples, the network is not allowed (and/or is not configured) toindicate to and/or instruct (via a DCI, for example) the UE to performUL transmission with spatial multiplexing if (and/or when) the networkconfigures the UE with UL spatial multiplexing and UL skipping (and/orif and/or when the UE is configured with UL spatial multiplexing and ULskipping). In some examples, the network is not allowed (and/or is notconfigured) to schedule the UE with a DCI format associated with spatialmultiplexing (e.g., scheduling the UE with a DCI format associated withspatial multiplexing may cause the UE perform UL transmission withmultiple antenna ports) if (and/or when) the network configures the UEwith UL spatial multiplexing and UL skipping (and/or if and/or when theUE is configured with UL spatial multiplexing and UL skipping). In someexamples, the network shall indicate to and/or instruct (via a DCI, forexample) the UE to perform UL transmission without spatial multiplexingif (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping (and/or if and/or when the UE is configuredwith UL spatial multiplexing and UL skipping). In some examples, thenetwork shall indicate to and/or instruct (via a DCI, for example) theUE to perform UL transmission with a single antenna port if (and/orwhen) the network configures the UE with UL spatial multiplexing and ULskipping (and/or if and/or when the UE is configured with UL spatialmultiplexing and UL skipping). In some examples, the network shallschedule the UE with DCI format 0 (to perform UL transmission with asingle antenna port, for example) if (and/or when) the networkconfigures the UE with UL spatial multiplexing and UL skipping (and/orif and/or when the UE is configured with UL spatial multiplexing and ULskipping).

In some examples, one, some and/or all of the above restrictions tonetwork configuration and/or network indication may be applied if(and/or when) the network is unsure about and/or does not know availabledata of the UE (e.g., available data at the UE side) and/or if (and/orwhen) the network determines (and/or realizes) that an amount ofavailable data of the UE (e.g., an amount of available data at the UEside) is smaller than a threshold amount of data. In some examples, one,some and/or all of the above restrictions to network configurationand/or network indication may not be applied if (and/or when) thenetwork determines (and/or realizes) that an amount of available data ofthe UE (e.g., an amount of available data at the UE side) is larger thanthe threshold amount of data. In some examples, the network maydetermine (and/or realize) the amount of available data of the UE basedon a buffer status report from a UE. In some examples, one, some and/orall of the above restrictions to network configuration and/or networkindication may be applied if (and/or when) the network does not receivea buffer status report from the UE (and/or the network has not receiveda buffer status report from the UE for over a threshold duration oftime), if (and/or when) the network does not have a latest (e.g., mostrecent) buffer status information of the UE, if (and/or when) thenetwork receives a scheduling request from the UE, if (and/or when) thenetwork schedules the UE in response to a scheduling request from theUE, if (and/or when) the network receives a buffer status report,associated with the UE, that is indicative of an amount of availabledata smaller than a threshold amount of data, if (and/or when) thenetwork receives a buffer status report, associated with the UE, that isindicative of an amount of available data that is smaller than a size ofone transport block, and/or if (and/or when) the network receives abuffer status report, associated with the UE, that is indicative of anamount of available data that results in data (e.g., available data ofthe UE, such as all available data of the UE) being included in a singletransport block while no data (e.g., no available data of the UE) isincluded in another transport block. In some examples, one, some and/orall of the above restrictions to network configuration and/or networkindication may not be applied if (and/or when) the network receives abuffer status report, associated with the UE, that is indicative of anamount of available data larger than a threshold amount of data, if(and/or when) the network receives a buffer status report, associatedwith the UE, that is indicative of an amount of available data largerthan a size of one transport block, and/or if (and/or when) the networkreceives a buffer status report, associated with the UE, that isindicative of an amount of available data that results in data (e.g.,the available data of the UE) being included in both transport blocks ofthe two transport blocks (such as where a first portion of the availabledata is included in a first transport block of the two transport blocksand a second portion of the available data is included in a secondtransport block of the two transport blocks).

In one embodiment, the network may configure the UE with UL spatialmultiplexing and UL skipping. In some examples, if (and/or when) one ormore first conditions are met: the network is not allowed (and/or is notconfigured) to indicate to and/or instruct (via a DCI, for example) theUE to perform UL transmission with two transport blocks; and/or thenetwork is not allowed (and/or is not configured) to indicate, to the UE(via a DCI, for example), two UL grants for a first TTI; and/or thenetwork is not allowed (and/or is not configured) to indicate to and/orinstruct (via a DCI, for example) the UE to enable both transport blocksof two transport blocks; and/or the network is not allowed (and/or isnot configured) to indicate (via a DCI format associated with spatialmultiplexing, for example), to the UE, neither a first combination ofI_(MCS)=0 and N_(PRB)>1 nor a second combination of I_(MCS)=28 andN_(PRB)=1, for two transport blocks (and/or for both transport blocks ofthe two transport blocks); and/or the network is not allowed (and/or isnot configured) to enable, with DCI, spatial multiplexing for the UE;and/or the network is not allowed (and/or is not configured) to indicateto and/or instruct (via a DCI, for example) the UE to perform ULtransmission with spatial multiplexing; and/or the network is notallowed (and/or is not configured) to schedule the UE with a DCI formatassociated with spatial multiplexing (e.g., scheduling the UE with a DCIformat associated with spatial multiplexing may cause the UE perform ULtransmission with multiple antenna ports); and/or the network shallindicate to and/or instruct (via a DCI, for example) the UE to performUL transmission with a single transport block; and/or the network shallenable a single transport block (e.g., one transport block of twotransport blocks), such as enable a single transport block associatedwith the UE; and/or the network shall indicate to and/or instruct (via aDCI, for example) the UE to enable a single transport block; and/or thenetwork shall disable one transport block (e.g., one transport block oftwo transport blocks), such as one transport block associated with theUE; and/or the network shall indicate to and/or instruct (via a DCI, forexample) the UE to disable one transport block; and/or the network shallindicate (via a DCI format associated with spatial multiplexing, forexample), to the UE, either a first combination of I_(MCS)=0 andN_(PRB)>1 or a second combination of I_(MCS)=28 and N_(PRB)=1 for atransport block; and/or shall schedule the UE with a DCI format 0 or aDCI format associated with spatial multiplexing wherein either a firstcombination of I_(MCS)=0 and N_(PRB)>1 or a second combination ofI_(MCS)=28 and N_(PRB)=1 for a transport block is signaled and/orindicated in the DCI format associated with spatial multiplexing; and/orthe network shall indicate to and/or shall instruct (via a DCI, forexample) the UE to perform UL transmission without spatial multiplexing;and/or the network shall indicate to and/or shall instruct (via a DCI,for example) the UE to perform UL transmission with a single antennaport; and/or shall schedule the UE with a DCI format 0, wherein the oneor more first conditions may comprise a condition that is met if (and/orwhen) the network is unsure about available data of the UE (e.g.,available data at the UE side), a condition that is met if (and/or when)the network does not know and/or determine an amount of available dataof the UE (e.g., an amount of available data at the UE side), acondition that is met if (and/or when) the network determines (and/orrealizes) that an amount of available data of the UE (e.g., an amount ofavailable data at the UE side) is smaller than a threshold amount ofdata, a condition that is met if (and/or when) the network does notreceive (and/or has not received) a buffer status report from the UE(for over a threshold duration of time, for example), a condition thatis met if (and/or when) the network does not have a latest (e.g., mostrecent) buffer status information of the UE, a condition that is met if(and/or when) the network receives a scheduling request from the UE, acondition that is met if (and/or when) the network schedules the UE inresponse to a scheduling request from the UE, a condition that is met if(and/or when) the UE is scheduled by the network in response to ascheduling request from the UE, a condition that is met if (and/or when)the network receives a buffer status report, associated with the UE,that is indicative of an amount of available data smaller than athreshold amount of data, a condition that is met if (and/or when) thenetwork receives a buffer status report, associated with the UE, that isindicative of an amount of available data that is smaller than a size ofone transport block, a condition that is met if (and/or when) thenetwork receives a buffer status report, associated with the UE, that isindicative of an amount of available data that results in data (e.g.,available data of the UE, such as all available data of the UE) beingincluded in a single transport block while no data (e.g., no availabledata of the UE) is included in another transport block, a condition thatis met if (and/or when) the network configures the UE with UL spatialmultiplexing and UL skipping, and/or a condition that is met if (and/orwhen) the UE is configured (by the network, for example) with UL spatialmultiplexing and UL skipping. In some examples, if (and/or when) one ormore second conditions are met: the network may indicate to and/orinstruct (via a DCI, for example) the UE to perform UL transmission withtwo transport blocks; and/or the network may indicate, to the UE (via aDCI, for example), two UL grants for a second TTI; and/or the networkmay indicate to and/or instruct (via a DCI, for example) the UE toenable both transport blocks of two transport blocks; and/or the networkmay transmit an indication to the UE (via a DCI format associated withspatial multiplexing, for example) so that neither a first combinationof I_(MCS)=0 and N_(PRB)>1 nor a second combination of I_(MCS)=28 andN_(PRB)=1 are satisfied for one transport block (of two transportblocks, for example); and/or the network may enable, with DCI, spatialmultiplexing for the UE; and/or the network may indicate to and/orinstruct (via a DCI, for example) the UE to perform UL transmission withspatial multiplexing and/or with multiple antenna ports; and/or thenetwork may schedule the UE with a DCI format associated with spatialmultiplexing (e.g., scheduling the UE with a DCI format associated withspatial multiplexing may cause the UE perform UL transmission withmultiple antenna ports), wherein the one or more second conditions maycomprise a condition that is met if (and/or when) the network determines(and/or realizes) that an amount of available data of the UE (e.g., anamount of available data at the UE side) is larger than a thresholdamount of data, a condition that is met if (and/or when) the networkreceives a buffer status report, associated with the UE, that isindicative of an amount of available data larger than a threshold amountof data, a condition that is met if (and/or when) the network receives abuffer status report, associated with the UE, that is indicative of anamount of available data larger than a size of one transport block, acondition that is met if (and/or when) the network receives a bufferstatus report, associated with the UE, that is indicative of an amountof available data that results in data (e.g., the available data of theUE) being included in both transport blocks of the two transport blocks(such as where a first portion of the available data is included in afirst transport block of the two transport blocks and a second portionof the available data is included in a second transport block of the twotransport blocks), a condition that is met if (and/or when) the networkconfigures the UE with UL spatial multiplexing and UL skipping, and/or acondition that is met if (and/or when) the UE is configured (by thenetwork, for example) with UL spatial multiplexing and UL skipping.Alternatively and/or additionally, if (and/or when) the one or moresecond conditions are met, the network may be allowed (and/orconfigured) to: indicate to and/or instruct (via a DCI, for example) theUE to perform UL transmission with two transport blocks; and/orindicate, to the UE (via a DCI, for example), two UL grants for a TTI;and/or indicate to and/or instruct (via a DCI, for example) the UE toenable both transport blocks of two transport blocks.

In some examples, the network may configure UL spatial multiplexing byconfiguring transmission mode 2 (for uplink, for example). For example,the network may configure the UE with transmission mode 2 (for uplink,for example).

Throughout the present disclosure, one, some, and/or all instances of“configure UL spatial multiplexing” and/or “configure the UE with ULspatial multiplexing” may correspond to, may be supplemented with and/ormay be replaced by “configure transmission mode 2 (for uplink, forexample)” and/or “configure the UE with transmission mode 2 (for uplink,for example)”, respectively.

Throughout the present disclosure, one, some, and/or all instances of“TTI” may comprise and/or may be a subframe, a slot, a subslot, shortTTI (sTTI), 2 symbols, 3 symbols, and/or 7 symbols (and/or a differentnumber of symbols).

Throughout the present disclosure, one, some, and/or all instances of“UL transmission” may comprise and/or may be a PUSCH transmission.

Throughout the present disclosure, one, some, and/or all instances of“is not allowed to” may correspond to, may be supplemented with and/ormay be replaced by “prevents”, “is prevented from”, “prohibits” and/or“is prohibited from”. In an example, “the network is not allowed toperform a first action” may be replaced by and/or may be supplementedwith “the network prevents performance of the first action”, “thenetwork is prevented from performing the first action”, “the networkprohibits performance of the first action”, and/or “the network isprohibited from performing the first action”.

Throughout the present disclosure, one, some, and/or all instances of“the network is not allowed to (and/or is not configured to) configure”may correspond to, may be supplemented with and/or may be replaced by“the UE is not expected to be configured”. In an example, “the networkis not allowed to (and/or is not configured to) configure the UE with afirst configuration” may be replaced by and/or may be supplemented with“the UE is not expected to be configured with the first configuration”.

Throughout the present disclosure, one, some and/or all instances of“the network is not allowed to (and/or is not configured to) indicateand/or instruct” may correspond to, may be supplemented with and/or maybe replaced by “the UE is not expected to be indicated and/orinstructed”. In an example, “the network is not allowed to (and/or isnot configured to) indicate to and/or instruct the UE to perform a firstaction” may be replaced by and/or may be supplemented with “the UE isnot expected to be indicated to and/or instructed to perform the firstaction”.

Throughout the present disclosure, one, some and/or all instances of“the network is not allowed to (and/or is not configured to) schedule”may correspond to, may be supplemented with and/or may be replaced by“the UE is not expected to be scheduled”. In an example, “the network isnot allowed to (and/or is not configured to) schedule the UE with a DCIformat” may be replaced by and/or may be supplemented with “the UE isnot expected to be scheduled with the DCI format”.

Throughout the present disclosure, one, some and/or all instances of“TTI” may correspond to and/or may be replaced by “given TTI”.

With respect to one or more embodiments of the present disclosure, theUE may be configured by the network with a single cell.

Throughout the present disclosure, UL grants associated with a TTI, ULgrants for a TTI and/or UL grants at a TTI may be used interchangeably.With respect to one or more embodiments of the present disclosure, ULgrants associated with a TTI, UL grants for a TTI and/or UL grants at aTTI may be for one serving cell (e.g., for a HARQ entity).

Throughout the present disclosure, UL grants associated with a TTI, ULgrants for a TTI and/or UL grants at a TTI may be used interchangeably.With respect to one or more embodiments of the present disclosure, ULgrants associated with a TTI, UL grants for a TTI and/or UL grants at aTTI may correspond to UL grants received for the TTI.

Throughout the present disclosure, MAC PDUs associated with a TTI, MACPDUs for a TTI and/or MAC PDUs at a TTI may be used interchangeably.With respect to one or more embodiments of the present disclosure, MACPDUs associated with a TTI, MAC PDUs for a TTI and/or MAC PDUs at a TTImay correspond to MAC PDUs that are generated for transmission via ULgrants received for the TTI.

Throughout the present disclosure, for the TTI, at the TTI and/orassociated with the TTI may be used interchangeably.

To solve one or more of the aforementioned issues (e.g., at least one ofan issue that a MAC of a UE transmits merely one transport block to aPHY even though the MAC receives two UL grants with UL spatialmultiplexing, where the PHY may expect two transport blocks, an issuethat the PHY may be unable to generate a 4 layer transmission properlywith merely one transport block, etc.), the UE may not skip an ULtransmission (and/or any UL transmission) for UL spatial multiplexing.The UE may not skip UL transmission and/or may generate two MAC PDUs fora TTI when and/or if the UE receives two UL grants for the TTI (and/orthe UE may not skip UL transmission and/or may generate two MAC PDUs fora TTI in response to receiving two UL grants for the TTI). The UE maynot skip UL transmission and/or may generate two MAC PDUs for a TTI whenthe UE is configured for UL spatial multiplexing. The UE may not skip ULtransmission and/or may generate two MAC PDUs for a TTI when and/or ifUL grants associated with the TTI are for spatial multiplexingtransmission. The UE may not skip UL transmission and/or may generatetwo MAC PDUs for a TTI when and/or if the UE receives two UL grants forthe TTI and a first UL grant of the two UL grants is able to accommodateavailable data of the UE (and/or if a first MAC PDU of the two MAC PDUsaccommodates the available data of the UE and there is merely paddingleft for inclusion in a second MAC PDU of the two MAC PDUs). The UE maynot skip UL transmission and/or may generate two MAC PDUs for a TTI whenand/or if the UE receives two UL grants for the TTI and a first MAC PDUof the two MAC PDUs (and/or a MAC PDU associated with a first UL grantof the two UL grants) merely comprises padding. The UE may not skip ULtransmission and/or may generate two MAC PDUs for a TTI when and/or ifthe UE receives two UL grants for the TTI and a first MAC PDU of the twoMAC PDUs (and/or a MAC PDU associated with a first UL grant of the twoUL grants) merely comprises a MAC CE, for a padding BSR or a periodicBSR, with zero MAC SDUs (where the first MAC PDU and/or the MAC CE donot comprise any MAC SDUs). The UE may not skip UL transmission and/ormay generate two MAC PDUs for a TTI when and/or if the UE receives twoUL grants for the TTI and a first UL grant of the two UL grants is ableto accommodate available data (e.g., all available data) of the UE(and/or if a first MAC PDU of the two MAC PDUs accommodates theavailable data (e.g., all available data of the UE) and there is merelypadding left for inclusion in a second MAC PDU of the two MAC PDUs). TheUE may not skip UL transmission and/or may generate two MAC PDUs for aTTI when and/or if the UE receives two UL grants for the TTI, a firstMAC PDU of the two MAC PDUs (and/or a MAC PDU associated with a first ULgrant of the two UL grants) merely comprises a MAC CE for a padding BSRor a periodic BSR with zero MAC SDUs (where the first MAC PDU and/or theMAC CE do not comprise any MAC SDUs), and a second MAC PDU of the twoMAC PDUs (and/or a MAC PDU associated with a second UL grant of the twoUL grants) comprises data (e.g., available data of the UE) or a MAC SDU.

In some examples, a Multiplexing and assembly entity may separate and/orsplit available data of the UE into MAC PDUs (e.g., two MAC PDUs)associated with a TTI (and/or the MAC PDUs for the TTI and/or at theTTI). The UE may separate and/or split padding (and/or a MAC CE, forpadding BSR and/or periodic BSR, with zero MAC SDUs) to the MAC PDUsassociated with a TTI. In some examples, the UE ensures that each of theMAC PDUs (e.g., both of the two MAC PDUs) comprises UE data.Alternatively and/or additionally, the UE may ensure that each of theMAC PDUs (e.g., both of the two MAC PDUs) comprises one or more MACSDUs. Alternatively and/or additionally, the UE may ensure that each ofthe MAC PDUs (e.g., both of the two MAC PDUs) comprises data andpadding. Alternatively and/or additionally, the UE may ensure that eachof the MAC PDUs (e.g., both of the two MAC PDUs) comprises a MAC PDU andat least one of padding, a MAC CE for padding BSR, a periodic BSR withzero MAC SDUs, etc. Alternatively and/or additionally, the UE may ensurethat each of the MAC PDUs (e.g., both of the two MAC PDUs) does notmerely comprise padding (e.g., the UE may ensure that each of the MACPDUs, such as both of the two MAC PDUs, comprises data other thanpadding). Alternatively and/or additionally, the UE may ensure that theMAC PDUs do not merely comprise padding (e.g., the UE may ensure that atleast one of the MAC PDUs, comprises data other than padding).Alternatively and/or additionally, the UE may ensure that each of theMAC PDUs (e.g., both of the two MAC PDUs) do not merely comprise a MACCE for padding BSR and/or do not merely comprise a MAC CE for periodicBSR with zero MAC SDUs. Alternatively and/or additionally, the UE mayensure that the MAC PDUs do not merely comprise a MAC CE for padding BSRand/or do not merely comprise a MAC CE for periodic BSR with zero MACSDUs (e.g., the UE may ensure that at least one of the MAC PDUs,comprises data other than a MAC CE for padding BSR and/or a MAC CE forperiodic BSR with zero MAC SDUs). In an example, a MAC PDU of the MACPDUs may accommodate available data (e.g., all available data) of theUE. In some examples, the UE ensures that each of the MAC PDUs (e.g.,both of the two MAC PDUs) comprises UE data even if one MAC PDU of theMAC PDUs can accommodate the available data (e.g., all available data ofthe UE). In some examples, the UE generates two PDUs (e.g., two MACPDUs) since both of the two PDUs comprise UL data (and/or the UE maygenerate the two PDUs such that each PDU of the two PDUs comprises ULdata, such as where a first PDU of the two PDUs comprises first UL dataand a second PDU of the two PDUs comprises second UL data). The UL datamay correspond to at least some of the available data of the UE. In someexamples, the UE generates two PDUs (e.g., two MAC PDUs) since both ofthe two PDUs do not merely comprise padding (such as where a first PDUof the two PDUs comprises first data other than padding and/or a secondPDU of the two PDUs comprises second data other than padding). In someexamples, the UE generates two PDUs (e.g., two MAC PDUs) since both ofthe two PDUs do not merely comprise a MAC CE, for padding BSR orperiodic BSR, with zero MAC SDUs (and/or the UE may generate the twoPDUs such that both of the two PDUs do not comprise merely a MAC CE, forpadding BSR or periodic BSR, with zero MAC SDUs). The UE may separateand/or split the available data to the MAC PDUs associated with a TTI(and/or the MAC PDUs for the TTI and/or at the TTI) if UL skipping isconfigured. The UE may separate and/or split padding to the MAC PDUsassociated with a TTI (and/or the MAC PDUs for the TTI and/or at theTTI) if UL skipping is configured.

In some examples, the UE does not separate and/or split available dataof the UE (e.g., all available data of the UE) to MAC PDUs associatedwith a TTI (and/or the MAC PDUs for the TTI and/or the MAC PDUs at theTTI) if one MAC PDU cannot accommodate the available data of the UE(e.g., all available data of the UE). In some examples, the UE does notseparate and/or split padding (and/or the MAC CE, for padding BSR and/orperiodic BSR, with zero MAC SDUs) to MAC PDUs associated with a TTI(and/or the MAC PDUs for the TTI and/or the MAC PDUs at the TTI) if oneMAC PDU cannot accommodate available data of the UE (e.g., all availabledata of the UE). The UE may include data in a first MAC PDU (of two MACPDUs, for example) and include second data and padding (and/or the MACCE, for padding BSR and/or periodic BSR, with zero MAC SDUs) in a secondMAC PDU (of the two MAC PDUs) if one MAC PDU (of the two MAC PDUs)cannot accommodate available data of the UE (e.g., all available data ofthe UE). The UE may include first data in a first MAC PDU (of two MACPDUs, for example) and include second data and padding in a second MACPDU (of the two MAC PDUs, for example) if the two MAC PDUs canaccommodate available data of the UE (e.g., all available data of theUE). In some examples, the UE does not separate and/or split availabledata of the UE (e.g., all available data of the UE) to MAC PDUsassociated with a TTI (and/or the MAC PDUs for the TTI and/or the MACPDUs at the TTI) if UL skipping is not configured. In some examples, theUE does not separate and/or split padding to MAC PDUs associated with aTTI (and/or the MAC PDUs for the TTI and/or the MAC PDUs at the TTI) ifUL skipping is not configured.

In some examples, the Multiplexing and assembly entity may ignore one ormore conditions of not generating MAC PDU (e.g., one or more conditionsbased on which the Multiplexing and assembly entity may not generate aMAC PDU, such as a condition that is met if generating the MAC PDU wouldresult in the MAC PDU comprising no available data of the UE).Alternatively and/or additionally, a HARQ entity may indicate to and/orinstruct the Multiplexing and assembly entity to generate a padding MACPDU (e.g., a MAC PDU comprising padding and/or not comprising availabledata of the UE). Alternatively and/or additionally, the HARQ entity mayobtain the padding MAC PDU from a HARQ process buffer (e.g., a secondHARQ process buffer associated with a second HARQ process other than arelated HARQ process that is associated with and/or allocated to the TTIand/or a UL grant associated with the padding MAC PDU, where the secondHARQ process may be associated with and/or allocated to the TTI and/or asecond UL grant for the TTI).

The network may configure the UE with UL spatial multiplexing and afirst parameter indicative of UL skipping (e.g., skip UplinkTxDynamic).The UE configured with UL spatial multiplexing may receive two UL grantsfor a TTI.

Example 1-1: Separate Data to MAC PDUs

In Example 1-1, the UE may allocate available data of the UE separatelyto MAC PDUs associated with a TTI (and/or the MAC PDUs for the TTIand/or the MAC PDUs at the TTI) when and/or if the UE receives UL grants(e.g., two UL grants) for the TTI. Alternatively and/or additionally,the UE may allocate the available data separately to the MAC PDUs (e.g.,the MAC PDUs associated with the TTI, the MAC PDUs for the TTI and/orthe MAC PDUs at the TTI) when and/or if the UE is configured for ULspatial multiplexing. Alternatively and/or additionally, the UE mayallocate the available data separately to the MAC PDUs (e.g., the MACPDUs associated with the TTI, the MAC PDUs for the TTI and/or the MACPDUs at the TTI) when and/or if the UL grants associated with the TTIare for spatial multiplexing transmission.

The UE may allocate UL resources to logical channels that are allowed totransmit (with consideration of the sum of capacities of the UL grantsassociated with the TTI, for example). The UL resources may be allocatedto the logical channels based on the capacities of the UL grantsassociated with the TTI (e.g., the UL resources may be allocated to thelogical channels based on the sum of the capacities). Alternativelyand/or additionally, the logical channels may be identified based on thecapacities of the UL grants associated with the TTI (e.g., the logicalchannels may be identified based on the sum of the capacities).

Example 1-2: Generate MAC PDUs when (and/or in Response to) ReceivingTwo UL Grants Associated with a TTI

In Example 1-2, the UE may generate MAC PDUs (e.g., two MAC PDUs) when(and/or in response to) receiving two UL grants associated with a TTI(e.g., the UE may always generate MAC PDUs, such as two MAC PDUs, when(and/or in response to) receiving two UL grants associated with a TTI).For example, the UE may generate MAC PDUs (e.g., two MAC PDUs)associated with a TTI (and/or for the TTI and/or at the TTI), whenand/or if the UE receives two UL grants for the TTI, regardless ofwhether the UE has available data amounting to at least a thresholdamount of available data. In some examples, the threshold amount ofavailable data may correspond to an amount of available dataaccommodated by an UL grant of the two UL grants. For example, an amountof data of the available data of the UE being less than the thresholdamount of available data may indicate that the UE does not have enoughavailable data for the TTI and/or the two UL grants (e.g., merely one ULgrant of the two UL grants may accommodate all the available data).Alternatively and/or additionally, the UE may generate MAC PDUsassociated with a TTI (and/or for the TTI and/or at the TTI), inresponse to receiving two UL grants for the TTI, regardless of whetherthe UE has available data amounting to at least the threshold amount ofavailable data. During and/or in accordance with a LCP procedure(performed by the UE for performing an UL transmission, for example),the UE may not generate a MAC PDU if the UE does not have availabledata, a MAC entity of the UE is configured with a first parameter (e.g.,skip UplinkTxDynamic), a grant (e.g., an UL grant received by the UE) isaddressed to a C-RNTI, and the UE does not have two UL grants at a TTI(associated with the grant, for example).

Example 1-3: Generate MAC PDUs when Configured for UL SpatialMultiplexing

In Example 1-3, the UE may generate MAC PDUs (e.g., two MAC PDUs) when(and/or if) the UE is configured for UL spatial multiplexing (e.g., theUE may always generate MAC PDUs, such as two MAC PDUs, when (and/or if)the UE is configured for UL spatial multiplexing). For example, the UEmay generate MAC PDUs (e.g., two MAC PDUs), regardless of whether the UEhas available data amounting to the threshold amount of available data,when (and/or if) the UE is configured for UL spatial multiplexing.During and/or in accordance with a LCP procedure (performed by the UEfor performing an UL transmission, for example), the UE may not generatea MAC PDU if the UE does not have available data, a MAC entity of the UEis configured with a first parameter (e.g., skip UplinkTxDynamic), agrant (e.g., an UL grant received by the UE) is addressed to a C-RNTI,and the UE is not configured for UL spatial multiplexing.

Example 1-4: Generate MAC PDUs when the UL Grant is for SpatialMultiplexing Transmission

In Example 1-4, the UE may generate MAC PDUs (e.g., two MAC PDUs) when(and/or if) an UL grant (e.g., an UL grant received by the UE) is forspatial multiplexing transmission (e.g., the UE may always generate MACPDUs, such as two MAC PDUs, when (and/or if) an UL grant is for spatialmultiplexing transmission). For example, the UE may generate MAC PDUs(e.g., two MAC PDUs), regardless of whether the UE has available dataamounting to the threshold amount of available data, when (and/or if) anUL grant (e.g., an UL grant received by the UE) is for spatialmultiplexing transmission. During and/or in accordance with a LCPprocedure (performed by the UE for performing an UL transmission, forexample), the UE may not generate a MAC PDU if the UE does not haveavailable data, a MAC entity of the UE is configured with a firstparameter (e.g., skip UplinkTxDynamic), and a grant (e.g., an UL grantreceived by the UE) is addressed to a C-RNTI not for UL spatialmultiplexing.

Example 1-5: Indicate a Padding MAC PDU when (and/or in Response to)Receiving Two UL Grants for a TTI

In Example 1-5, if the UE does not obtain a MAC PDU associated with aTTI (and/or for the TTI and/or at the TTI), the UE may generate apadding MAC PDU when (and/or if) the UE has two UL grants for the TTI(and/or in response to the UE receiving the two UL grants for the TTI).For example, if a MAC PDU to transmit has not been obtained and the UEhas two UL grants for the TTI, the UE may indicate to and/or instructthe Multiplexing and assembly entity to generate a padding MAC PDU(e.g., a MAC PDU comprising padding and/or not comprising available dataof the UE).

Example 1-6: Indicate a Padding MAC PDU when Configured for UL SpatialMultiplexing

In Example 1-6, if the UE does not obtain a MAC PDU associated with aTTI (and/or for the TTI and/or at the TTI), the UE may generate apadding MAC PDU when (and/or if) the UE is configured for UL spatialmultiplexing. For example, if a MAC PDU to transmit has not beenobtained and a PHY of the UE is configured for UL spatial multiplexing,the UE may indicate to and/or instruct the Multiplexing and assemblyentity to generate a padding MAC PDU (e.g., a MAC PDU comprising paddingand/or not comprising available data of the UE).

Example 1-7: Indicate a Padding MAC PDU when the UL Grant is for SpatialMultiplexing Transmission

In Example 1-7, if the UE does not obtain a MAC PDU associated with aTTI (and/or for the TTI and/or at the TTI) for UL spatial multiplexing,the UE may generate a padding MAC PDU. For example, if a MAC PDU totransmit has not been obtained and a HARQ process (e.g., an identifiedHARQ process associated with and/or allocated to the TTI and/or an ULgrant associated with the MAC PDU) is for UL spatial multiplexing, theUE may indicate to and/or instruct the Multiplexing and assembly entityto generate a padding MAC PDU (e.g., a MAC PDU comprising padding and/ornot comprising available data of the UE).

Example 1-8: Obtain the MAC PDU from a Second HARQ Process Buffer when(and/or in Response to) Receiving Two UL Grants for a TTI

In Example 1-8, if the UE does not obtain a MAC PDU for the TTI, the UEmay obtain a MAC PDU from a second HARQ process buffer when (and/or if)the UE has two UL grants for the TTI (and/or in response to the UEreceiving the two UL grants for the TTI). For example, if a MAC PDU totransmit has not been obtained and the UE has the two UL grants for theTTI, the UE may obtain the MAC PDU from the second HARQ process bufferassociated with the TTI. In some examples, the second HARQ processbuffer may be associated with a second HARQ process other than a relatedHARQ process that is associated with and/or allocated to the TTI and/ora first UL grant for which the MAC PDU is generated, where the secondHARQ process may be associated with and/or allocated to the TTI and/or asecond UL grant for the TTI.

Example 1-9: Obtain the MAC PDU from a Second HARQ Process Buffer whenConfigured for UL Spatial Multiplexing

In Example 1-9, if the UE does not obtain a MAC PDU for a TTI, the UEmay obtain a MAC PDU from a second HARQ process buffer when (and/or if)the UE is configured for UL spatial multiplexing. For example, if a MACPDU to transmit has not been obtained and a PHY of the UE is configuredfor UL spatial multiplexing, the UE may obtain the MAC PDU from thesecond HARQ process buffer associated with the TTI. In some examples,the second HARQ process buffer may be associated with a second HARQprocess other than a related HARQ process that is associated with and/orallocated to the TTI and/or a first UL grant for which the MAC PDU isgenerated, where the second HARQ process may be associated with and/orallocated to the TTI and/or a second UL grant for the TTI.

Example 1-10: Obtain MAC PDU from a Second HARQ Process Buffer when theUL Grant is for Spatial Multiplexing Transmission

In Example 1-10, the UE may obtain a MAC PDU from a second HARQ processbuffer if the UE does not obtain a MAC PDU for the TTI for UL spatialmultiplexing. For example, if a MAC PDU to transmit has not beenobtained and a first HARQ process (e.g., an identified HARQ processassociated with and/or allocated to the TTI and/or an UL grantassociated with the MAC PDU) is for UL spatial multiplexing, the UE mayobtain the MAC PDU from the second HARQ process buffer associated withthe TTI. In some examples, the second HARQ process buffer may beassociated with a second HARQ process other than the first HARQ process,where the second HARQ process may be associated with and/or allocated tothe TTI and/or a second UL grant for the TTI.

In Examples 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, and/or 1-10,one and/or both of the MAC PDUs (e.g., the two MAC PDUs) associated withthe TTI may merely comprise padding, padding BSR, and/or periodic BSRwith zero MAC SDUs.

To solve one or more of the aforementioned issues (e.g., at least one ofan issue that a MAC of a UE transmits merely one transport block to aPHY even though the MAC receives two UL grants with UL spatialmultiplexing, where the PHY may expect two transport blocks, an issuethat the PHY may be unable to generate a 4 layer transmission properlywith merely one transport block, etc.), the UE may skip both ULtransmissions for UL spatial multiplexing for a TTI. In an example, whenthe UE receives two UL grants for a TTI (and/or in response to receivingthe two UL grants for the TTI), the UE may skip UL transmissions and/ormay not generate any MAC PDUs for the TTI if the UE an amount ofavailable data of the UE is less than a threshold amount of availabledata. Alternatively and/or additionally, when (and/or if) the UE isconfigured for UL spatial multiplexing, the UE may skip UL transmissionsand/or may not generate any MAC PDUs for a TTI if an amount of availabledata of the UE is less than the threshold amount of available data.Alternatively and/or additionally, when (and/or if) UL grants associatedwith a TTI are for UL spatial multiplexing transmission, the UE may skipUL transmissions and/or may not generate any MAC PDUs for the TTI if anamount of available data of the UE is less than the threshold amount ofavailable data. In some examples, the threshold amount of available datamay correspond to an amount of available data accommodated by an ULgrant of the two UL grants. For example, an amount of available data ofthe UE being less than the threshold amount of available data mayindicate that the UE does not have enough available data for the TTIand/or the two UL grants (e.g., merely one UL grant of the two UL grantsmay accommodate all the available data).

In some examples, the UE may skip UL transmissions (e.g., two ULtransmissions) for UL spatial multiplexing for a TTI when (and/or if)the UE receives two UL grants for the TTI and one of the two UL grantsis able to accommodate available data of the UE (e.g., all availabledata of the UE), wherein the two UL grants correspond to the ULtransmissions (e.g., the two UL transmissions) skipped by the UE.Alternatively and/or additionally, the UE may skip UL transmissions(e.g., two UL transmissions) for UL spatial multiplexing for a TTI.Alternatively and/or additionally, the UE may skip UL transmissions(e.g., two UL transmissions) for UL spatial multiplexing for a TTI when(and/or if) the UE receives two UL grants for the TTI and a MAC PDUassociated with one of the two UL grants merely comprises padding,wherein the two UL grants correspond to the UL transmissions (e.g., thetwo UL transmissions) skipped by the UE. Alternatively and/oradditionally, the UE may skip UL transmissions (e.g., two ULtransmissions) for UL spatial multiplexing for a TTI when (and/or if)the UE receives two UL grants for the TTI and a MAC PDU for the TTI(and/or a MAC PDU associated with one of the two UL grants) merelycomprises a MAC CE, for padding BSR or periodic BSR, with zero MAC SDUs.Alternatively and/or additionally, the UE may skip UL transmissions(e.g., two UL transmissions) for UL spatial multiplexing for a TTI when(and/or if) the UE receives two UL grants for the TTI, a first MAC PDUfor the TTI (and/or a first MAC PDU associated with a first UL grant ofthe two UL grants) merely comprises a MAC CE, for padding BSR orperiodic BSR, with zero MAC SDUs, and a second MAC PDU for the TTI(and/or a second MAC PDU associated with a second UL grant of the two ULgrants) comprises data (e.g., available data of the UE) and/or a MACSDU.

In some examples, when (and/or if) the UE receives two UL grants for aTTI and one of the two UL grants is able to accommodate available dataof the UE (e.g., all available data of the UE), the UE may skip ULtransmissions (e.g., two UL transmissions) and/or may not generate anyMAC PDUs for the TTI, wherein the two UL grants correspond to the ULtransmissions (e.g., the two UL transmissions) skipped by the UE.Alternatively and/or additionally, when (and/or if) the UE receives twoUL grants for a TTI and a MAC PDU associated with one of the two ULgrants merely comprises padding, the UE may skip UL transmissions (e.g.,two UL transmissions) and/or may not generate any MAC PDUs for the TTI,wherein the two UL grants correspond to the UL transmissions (e.g., thetwo UL transmissions) skipped by the UE. Alternatively and/oradditionally, when (and/or if) the UE receives two UL grants for a TTIand a MAC PDU for the TTI (and/or a MAC PDU associated with one of thetwo UL grants) merely comprises a MAC CE for padding BSR or periodic BSRwith zero MAC SDUs, the UE may skip UL transmissions (e.g., two ULtransmissions) and/or may not generate any MAC PDUs for the TTI, whereinthe two UL grants correspond to the UL transmissions (e.g., the two ULtransmissions) skipped by the UE. Alternatively and/or additionally,when (and/or if) the UE receives two UL grants for a TTI, a first MACPDU for the TTI (and/or a first MAC PDU associated with a first UL grantof the two UL grants) merely comprises a MAC CE, for padding BSR orperiodic BSR, with zero MAC SDUs, and a second MAC PDU for the TTI(and/or a second MAC PDU associated with a second UL grant of the two ULgrants) comprises data (e.g., available data of the UE) and/or a MACSDU, the UE may skip UL transmissions (e.g., two UL transmissions)and/or may not generate any MAC PDUs for the TTI, wherein the two ULgrants correspond to the UL transmissions (e.g., the two ULtransmissions) skipped by the UE.

In some examples, the Multiplexing and assembly entity may not generateany MAC PDU for a TTI when (and/or if) an amount of available data ofthe UE is less than the threshold amount of available data (e.g., theamount of available data of the UE being less than the threshold amountof data may indicate that the UE does not have enough available data forthe TTI and/or two UL grants for the TTI). For example, a HARQ entity ofthe UE may discard a first MAC PDU if a second MAC PDU at the TTI is notobtained. Alternatively and/or additionally, the HARQ entity may notinstruct a PHY of the UE to generate a transmission if a MAC PDU (e.g.,any MAC PDU) of MAC PDUs (e.g., two MAC PDUs) associated with a TTI isnot obtained.

The network may configure the UE with UL spatial multiplexing and afirst parameter (e.g., skip UplinkTxDynamic). The UE may receive two ULgrants at (and/or for) a TTI.

Example 2-1: Not Generate a MAC PDU when (and/or in Response to)Receiving Two UL Grants for a TTI

In Example 2-1, when (and/or if) the UE has (and/or receives) two ULgrants for a TTI (and/or in response to receiving the two UL grants),the UE may not generate any MAC PDU for the TTI if an amount ofavailable data of the UE is less than the threshold amount of availabledata. During and/or in accordance with a LCP procedure (performed by theUE for performing an UL transmission, for example), the UE may notgenerate a MAC PDU if the UE does not have available data for UL grants(e.g., two UL grants) for a TTI (and/or an amount of available data ofthe UE is less than the threshold amount of available data), a MACentity of the UE is configured with a first parameter (e.g., skipUplinkTxDynamic), and a grant (e.g., an UL grant received by the UE) isaddressed to a C-RNTI.

Example 2-2: Discard a MAC PDU when (and/or in Response to) ReceivingTwo UL Grants at a TTI

In Example 2-2, when (and/or if) the UE has (and/or receives) two ULgrants for a TTI (and/or in response to receiving the two UL grants),the UE may discard a first MAC PDU associated with the TTI if a secondMAC PDU associated with the TTI is not (and/or cannot be) obtained.Alternatively and/or additionally, if a first MAC PDU associated with aTTI has not been obtained, the UE may discard a second MAC PDUassociated with the TTI. If the second MAC PDU associated with the TTIis not (and/or cannot be) obtained, the UE may discard the first MACPDU. The UE may flush a related HARQ process buffer associated with theTTI and may not deliver the first MAC PDU associated with the TTI to aHARQ process (e.g., an identified HARQ process associated with and/orallocated to the TTI and/or an UL grant associated with the first MACPDU).

Example 2-3: Not Instruct PHY to Generate a Transmission when (and/or inResponse to) Receiving Two UL Grants for a TTI

In Example 2-3, when (and/or if) the UE has (and/or receives) two ULgrants for a TTI (and/or in response to receiving the two UL grants),the UE may not instruct a PHY of the UE to generate a transmission if aMAC PDU associated with a TTI is not obtained (and/or the UE may notinstruct the PHY to generate a transmission if both MAC PDUs of two MACPDUs associated with the TTI are not obtained). Alternatively and/oradditionally, if the UE receives two UL grants for a TTI, a first MACPDU associated with the TTI is not obtained and a second MAC PDUassociated with the TTI is obtained, the UE may instruct the PHY togenerate a transmission for the second MAC PDU. Alternatively and/oradditionally, if the first MAC PDU and the second MAC PDU are notobtained, the UE may flush a related HARQ process buffer associated withthe TTI.

The UE may be configured with UL spatial multiplexing and UL skipping.In some examples, the UE receives a DCI indicating UL transmission fortwo transport blocks. The DCI may be a DCI format associated withspatial multiplexing. The DCI may be DCI format 4. In some examples, theDCI enables two transport blocks. In some examples, the DCI indicatesneither a first combination of I_(MCS)=0 and N_(PRB)>1, nor a secondcombination of I_(MCS)=28 and N_(PRB)=1, for two transport blocks(and/or for both transport blocks of the two transport blocks). Forexample, the DCI may not indicate the first combination nor the secondcombination for either transport block of the two transport blocks. Insome examples, the UE (e.g., a MAC of the UE) generates a first PDU(e.g., one PDU) for a first transport block of the two transport blocks.In some examples, the UE (e.g., the MAC) does not generate a PDU for asecond transport block of the two transport blocks. For example, the UE(e.g., the MAC) may not generate a PDU for the second transport block ofthe two transport blocks due to UL skipping. Alternatively and/oradditionally, the UE (e.g., the MAC) may not generate a PDU for thesecond transport block of the two transport blocks due to one PDU (e.g.,the first PDU for the first transport block) being sufficient toaccommodate available data (e.g., all available data) of the UE.Alternatively and/or additionally, the UE (e.g., the MAC) may notgenerate a PDU for the second transport block of the two transportblocks due to a PDU for the second transport block comprising merelypadding and/or due to there being merely padding left for inclusion in aPDU for the second transport block after generating the first PDUsufficient to accommodate available data (e.g., all available data) ofthe UE (and/or the UE may not generate the PDU for the second transportblock if generation of the PDU would result in the PDU comprising merelypadding). Alternatively and/or additionally, the UE (e.g., the MAC) maynot generate a PDU for the second transport block of the two transportblocks due to a PDU for the second transport block comprising merely aMAC CE, for padding BSR or periodic BSR, with zero MAC SDUs (such aswhere the MAC CE and/or the PDU do not comprise any MAC SDU) and/or dueto there being merely the MAC CE left for inclusion in a PDU for thesecond transport block after generating the first PDU sufficient toaccommodate available data (e.g., all available data) of the UE (and/orthe UE may not generate the PDU for the second transport block ifgeneration of the PDU would result in the PDU comprising merely the MACCE, for padding BSR or periodic BSR, with zero MAC SDUs).

In some examples, the UE (e.g., a PHY of the UE) does not perform ULtransmission (e.g., PUSCH transmission) in response to the DCI. Forexample, the UE (e.g., the PHY) may not perform UL transmission (e.g.,PUSCH transmission) in response to the DCI if one MAC PDU is generated(e.g., if a MAC PDU is generated for a first transport block of the twotransport blocks and a MAC PDU is not generated for a second transportblock of the two transport blocks). Alternatively and/or additionally,the UE (e.g., the PHY) may not perform UL transmission (e.g., PUSCHtransmission) in response to the DCI if a MAC PDU for a first transportblock of the two transport blocks or a MAC PDU for a second transportblock of the two transport blocks is not generated. Alternatively and/oradditionally, the UE (e.g., the PHY) may not perform UL transmission(e.g., PUSCH transmission) in response to the DCI if merely one MAC PDUis generated (e.g., if a MAC PDU is generated for a first transportblock of the two transport blocks and a MAC PDU is not generated for asecond transport block of the two transport blocks). In some examples,the UE (e.g., the PHY) performs UL transmission (e.g., PUSCHtransmission) in response to the DCI if two MAC PDUs are generated forthe two transport blocks (e.g., if a first MAC PDU is generated for afirst transport block of the two transport blocks and a second MAC PDUis generated for a second transport block of the two transport blocks).For example, the UE (e.g., the PHY) may perform UL transmission (e.g.,PUSCH transmission) in response to the DCI only if two MAC PDUs aregenerated for the two transport blocks (e.g., if a first MAC PDU isgenerated for a first transport block of the two transport blocks and asecond MAC PDU is generated for a second transport block of the twotransport blocks). Alternatively and/or additionally, the UE (e.g., thePHY) may not perform UL transmission (e.g., PUSCH transmission) inresponse to the DCI if no MAC PDU is generated and/or if merely one MACPDU is generated (e.g., if a MAC PDU is generated for a first transportblock of the two transport blocks and a MAC PDU is not generated for asecond transport block of the two transport blocks).

In some examples, the UE (e.g., the PHY) disables a transport block forUL transmission (e.g., PUSCH transmission), such as the UL transmissionperformed in response to the DCI. In some examples, the UE (e.g., thePHY) disables a transport block for the UL transmission (e.g., PUSCHtransmission) even if the DCI does not disable the transport block. Insome examples, the UE (e.g., the PHY) disables a transport block for theUL transmission (e.g., PUSCH transmission) due to absence of one MACPDU. In some examples, the UE (e.g., the PHY) disables a transport blockfor the UL transmission (e.g., PUSCH transmission) if one MAC PDU isgenerated (e.g., if a MAC PDU is generated for a first transport blockof the two transport blocks and a MAC PDU is not generated for a secondtransport block of the two transport blocks). In some examples, the UE(e.g., the PHY) enables a transport block for the UL transmission (e.g.,PUSCH transmission) if one MAC PDU is generated (e.g., if a MAC PDU isgenerated for a first transport block of the two transport blocks and aMAC PDU is not generated for a second transport block of the twotransport blocks). In some examples, the UE (e.g., the PHY) disables aspecific and/or predefined transport block for the UL transmission(e.g., PUSCH transmission) if one MAC PDU is generated (e.g., if a MACPDU is generated for a first transport block of the two transport blocksand a MAC PDU is not generated for a second transport block of the twotransport blocks). In some examples, the UE (e.g., the PHY) disables TB1for the UL transmission (e.g., PUSCH transmission) if one MAC PDU isgenerated (e.g., if a MAC PDU is generated for a first transport blockof the two transport blocks and a MAC PDU is not generated for a secondtransport block of the two transport blocks). In some examples, the UE(e.g., the PHY) disables TB2 for the UL transmission (e.g., PUSCHtransmission) if one MAC PDU is generated (e.g., if a MAC PDU isgenerated for a first transport block of the two transport blocks and aMAC PDU is not generated for a second transport block of the twotransport blocks). In some examples, the UE (e.g., the PHY) enables atransport block other than the transport block disabled by the UE (e.g.,the PHY).

In some examples, the UE (e.g., the PHY) disables a specific and/orpredefined codeword for the UL transmission (e.g., PUSCH transmission)if one MAC PDU is generated (e.g., if a MAC PDU is generated for a firsttransport block of the two transport blocks and a MAC PDU is notgenerated for a second transport block of the two transport blocks). Forexample, the UE (e.g., the PHY) may disable codeword 1 for the ULtransmission (e.g., PUSCH transmission) if one MAC PDU is generated(e.g., if a MAC PDU is generated for a first transport block of the twotransport blocks and a MAC PDU is not generated for a second transportblock of the two transport blocks). Alternatively and/or additionally,the UE (e.g., the PHY) may disable codeword 0 for the UL transmission(e.g., PUSCH transmission) if one MAC PDU is generated (e.g., if a MACPDU is generated for a first transport block of the two transport blocksand a MAC PDU is not generated for a second transport block of the twotransport blocks). In some examples, the UE (e.g., the PHY) enables acodeword other than the codeword disabled by the UE (e.g., the PHY). Insome examples, the UE uses an enabled transport block to carry agenerated PDU (e.g., a MAC PDU generated for the enabled transportblock). Alternatively and/or additionally, the UE (e.g., the PHY) usesan enabled codeword to carry the generated PDU. In some examples, the UE(e.g., the PHY) uses layers, amounting to a first number of layers, toperform the UL transmission, wherein the first number of layers may bedifferent from a second number of layers indicated by the DCI. In someexamples, the UE (e.g., the PHY) may determine the first number oflayers (for performing the UL transmission) and/or the second number oflayers based on a field (e.g., “Precoding information and number oflayers” field) of the DCI. Alternatively and/or additionally, the UE(e.g., the PHY) may determine the first number of layers (for performingthe UL transmission) and/or the second number of layers based on a field(e.g., “Precoding information and number of layers” field) of the DCIand may assume that a transport block (one transport block) and/or acodeword (e.g., one codeword) is disabled. In some examples, the UE(e.g., the PHY) may determine the first number of layers (for performingthe UL transmission) based on an assumption that merely one codeword isenabled (even if the DCI indicates that two codewords are enabled, forexample). For example, the UE (e.g., the PHY) may determine the firstnumber of layers (for performing the UL transmission) based on firstinformation (e.g., a first column of a table) related to one codewordrather than second information (e.g., a second column of a table)related to two codewords (even if the DCI indicates that two codewordsare enabled, for example). Alternatively and/or additionally, the UE(e.g., the PHY) may determine a precoder based on a field (e.g.,“Precoding information and number of layers” field) of the DCI and mayuse the first information related to one codeword rather than the secondinformation related to two codewords (even if the DCI indicates that twocodewords are enabled). In some examples, the difference between thefirst number of layers (for performing the UL transmission) and thesecond number of layers (indicated by the DCI) is due to the UEdisabling a transport block (e.g., one transport block) (rather than thetransport block being disabled by DCI, for example). In some examples,the UE (e.g., PHY) uses a first precoder (for spatial multiplexing, forexample) to perform the UL transmission, wherein the first precoder maybe different from a second precoder (for spatial multiplexing, forexample) indicated by the DCI. The UE (e.g., the PHY) may use the firstprecoder to perform the UL transmission based on a field (e.g.,“Precoding information and number of layers” field) of the DCI. The UE(e.g., the PHY) may determine the first precoder (for spatialmultiplexing, for example) based on a field (e.g., “Precodinginformation and number of layers” field) of the DCI and may assume thata transport block (one transport block) and/or a codeword (e.g., onecodeword) is disabled. The UE (e.g., the PHY) may determine the firstprecoder based on a field (e.g., “Precoding information and number oflayers” field) of the DCI and may use the first information related toone codeword rather than the second information related to two codewords(even if the DCI indicates that two codewords are enabled, for example).The UE (e.g., the PHY) may determine the first precoder using the firstinformation related to one codeword rather than the second informationrelated to two codewords (even if the DCI indicates that two codewordsare enabled, for example). In some examples, the difference between thefirst precoder (for performing the UL transmission) and the secondprecoder (indicated by the DCI) is due to the UE disabling a transportblock (e.g., one transport block) (rather than the transport block beingdisabled by DCI, for example). In some examples, the UE (e.g., the PHY)disables a transport block for the UL transmission (e.g., PUSCHtransmission) if a MAC PDU (e.g., one MAC PDU of two MAC PDUs associatedwith a TTI) is not generated. In some examples, the UE (e.g., the PHY)disables a transport block for the UL transmission (e.g., PUSCHtransmission) if only one MAC PDU is generated (e.g., if a MAC PDU isgenerated for a first transport block of the two transport blocks and aMAC PDU is not generated for a second transport block of the twotransport blocks). In some examples, the UE (e.g., the PHY) does notdisable a transport block for the UL transmission (e.g., PUSCHtransmission) if two MAC PDUs are generated for the two transportblocks. In some examples, the UE (e.g., the PHY) enables the twoTransport Blocks for the UL transmission (e.g., PUSCH transmission) iftwo MAC PDU are generated for the two transport blocks. The ULtransmission (e.g., PUSCH transmission) may be a new transmission.Accordingly, a number of enabled codewords (e.g., one enabled codewordor two enabled codewords) and/or a number of enabled transport blocks(e.g., one enabled transport block or two enabled transport blocks) maybe identical to a number of generated MAC PDUs (e.g., one generated MACPDU or two generated MAC PDUs). The number of enabled codewords and/orthe number of enabled transport blocks being identical to the number ofgenerated MAC PDUs may enable the UE to perform a corresponding ULtransmission (e.g., PUSCH transmission).

Table 1 shows numbers of layers, bit fields mapped to index andTransmitted Precoding Matrix Indicators (TPMIs) in an example scenariowhere spatial multiplexing and/or UL transmission is performed with fourantenna ports.

TABLE 1 One codeword: Two codewords: Codeword 0 enabled Codeword 0enabled Codeword 1 disabled Codeword 1 enabled Bit field Bit fieldmapped mapped to index Message to index Message 0 1 layer: TPMI = 0 0 2layers: TPMI = 0 1 1 layer: TPMI = 1 1 2 layers: TPMI = 1 . . . . . . .. . . . . 23  1 layer: TPMI = 23 15  2 layers: TPMI = 15 24 2 layers:TPMI = 0  16 3 layers: TPMI = 0 25 2 layers: TPMI = 1  17 3 layers: TPMI= 1 . . . . . . . . . . . . 39  2 layers: TPMI = 15  27  3 layers: TPMI= 11 40-63 reserved 28 4 layers: TPMI = 0 29-63 Reserved

In some systems, if the DCI indicates that two codewords are enabled,the UE determines the first number of layers and the first precoder(e.g., TPMI) based on and/or in accordance with a two codeword column,of Table 1, corresponding to two codewords (e.g., a top row of the twocodeword column recites “Two codewords: Codeword 0 enabled Codeword 1enabled”). For example, in those systems, the UE may determine the firstnumber of layers and the first precoder based on a field (e.g.,“Precoding information and number of layers” field) of the DCI. Forexample, in those systems, if the field (e.g., “Precoding informationand number of layers” field) is equal to 1 and the DCI enables twocodewords, the UE may perform UL transmission with 2 transport blocks, 2layers, and TPMI=1. In an example, a value of the field (e.g.,“Precoding information and number of layers” field) corresponds tovalues of “Bit field mapped to index” in Table 1. Using one or more ofthe techniques herein, the UE may determine the first number of layersand the first precoder (e.g., TPMI) based on and/or in accordance with aone codeword column, of Table 1, corresponding to one codeword (e.g., atop row of the one codeword column recites: “One codeword: Codeword 0enabled Codeword 1 disabled). For example, the UE may determine thefirst number of layers and/or the first precoder based on and/or inaccordance with the one codeword column based on the UE disabling acodeword and/or a transport block (e.g., the UE may determine the firstnumber of layers and/or the first precoder based on and/or in accordancewith the one codeword column even if the DCI enables two codewords).Accordingly, using one or more of the techniques herein, if the field(e.g., “Precoding information and number of layers” field) is equal to 1(where the value of the field (e.g., “Precoding information and numberof layers” field) corresponds to values of “Bit field mapped to index”in Table 1, for example), the UE may perform UL transmission with onetransport block, one layer, and TPMI=1. Alternatively and/oradditionally, the UE may use a specific entry (e.g., a predefined and/orpre-configured entry) of the one codeword column. In an example, thespecific entry may correspond to a lowest entry (e.g., an entrycorresponding to “Bit field mapped to index” equal to 0), or other entry(e.g., an entry corresponding to “Bit field mapped to index” equal to afirst value, such as 0, 1, 2, 3, etc.). In an example in which thespecific entry of the one codeword column corresponds to “Bit fieldmapped to index” equal to 0, the UE may perform UL transmission with onetransport block, one layer and TPMI=0 (even if the field (e.g.,“Precoding information and number of layers” field) is not equal to 0).

In some examples, the UE (e.g., the PHY) performs UL transmission forone MAC PDU (e.g., one generated MAC PDU). For example, the UE (e.g.,the PHY) performs UL transmission for one MAC PDU if one MAC PDU isgenerated (e.g., if a MAC PDU is generated for a first transport blockof the two transport blocks and a MAC PDU is not generated for a secondtransport block of the two transport blocks). For example, if a firstMAC PDU of two MAC PDUs for a TTI is generated, and a second MAC PDU ofthe two MAC PDUs for the TTI is not generated, the UE (e.g., the PHY)may perform UL transmission for the first MAC PDU. In some examples, theUE (e.g., the PHY) does not perform UL transmission for the second MACPDU not generated by the UE (e.g., generated by the MAC of the UE).Alternatively and/or additionally, the UE (e.g., the PHY) may perform ULtransmission with a first codeword (e.g., one codeword) and/or a firsttransport block (e.g., one transport block). In some examples, the firstcodeword is codeword 0. Alternatively and/or additionally, the firstcodeword may be codeword 1. In some examples, the UE (e.g., the PHY)uses layers, amounting to a first number of layers, to perform the ULtransmission, wherein the first number of layers may be different from asecond number of layers indicated by the DCI. In some examples, the UE(e.g., the PHY) may determine the first number of layers (for performingthe UL transmission) and/or the second number of layers based on a field(e.g., “Precoding information and number of layers” field) of the DCI.Alternatively and/or additionally, the UE (e.g., the PHY) may determinethe first number of layers (for performing the UL transmission) and/orthe second number of layers based on a field (e.g., “Precodinginformation and number of layers” field) of the DCI and may assume thata transport block (one transport block) and/or a codeword (e.g., onecodeword) is disabled. In some examples, the UE (e.g., the PHY) maydetermine the first number of layers (for performing the ULtransmission) based on an assumption that merely one codeword is enabled(even if the DCI indicates that two codewords are enabled, for example).For example, the UE (e.g., the PHY) may determine the first number oflayers (for performing the UL transmission) based on first information(e.g., a first column of a table) related to one codeword rather thansecond information (e.g., a second column of a table) related to twocodewords (even if the DCI indicates that two codewords are enabled, forexample). Alternatively and/or additionally, the UE (e.g., the PHY) maydetermine a precoder based on a field (e.g., “Precoding information andnumber of layers” field) of the DCI and may use the first informationrelated to one codeword rather than the second information related totwo codewords (even if the DCI indicates that two codewords areenabled). In some examples, the difference between the first number oflayers (for performing the UL transmission) and the second number oflayers (indicated by the DCI) is due to the UE disabling a transportblock (e.g., one transport block) (rather than the transport block beingdisabled by DCI, for example). In some examples, the UE (e.g., PHY) usesa first precoder (for spatial multiplexing, for example) to perform theUL transmission, wherein the first precoder may be different from asecond precoder (for spatial multiplexing, for example) indicated by theDCI. The UE (e.g., the PHY) may use the first precoder to perform the ULtransmission based on a field (e.g., “Precoding information and numberof layers” field) of the DCI. The UE (e.g., the PHY) may determine thefirst precoder (for spatial multiplexing, for example) based on a field(e.g., “Precoding information and number of layers” field) of the DCIand may assume that a transport block (one transport block) and/or acodeword (e.g., one codeword) is disabled. The UE (e.g., the PHY) maydetermine the first precoder based on a field (e.g., “Precodinginformation and number of layers” field) of the DCI and may use thefirst information related to one codeword rather than the secondinformation related to two codewords (even if the DCI indicates that twocodewords are enabled, for example). The UE (e.g., the PHY) maydetermine the first precoder using the first information related to onecodeword rather than the second information related to two codewords(even if the DCI indicates that two codewords are enabled, for example).In some examples, the difference between the first precoder (forperforming the UL transmission) and the second precoder (indicated bythe DCI) is due to the UE disabling a transport block (e.g., onetransport block) (rather than the transport block being disabled by DCI,for example).

In some examples, the UE (e.g., the PHY) performs UL transmission fortwo MAC PDUs if two MAC PDUs are generated (for a TTI, for example). TheUE (e.g., the PHY) may perform the UL transmission with two codewords.Alternatively and/or additionally, the UE (e.g., the PHY) may use layers(amounting to a number of layers) and/or a precoder to perform the ULtransmission, wherein the number of layers and the precoder aredetermined based on a DCI (and/or the DCI is indicative of the number oflayers and the precoder). For example, if the two MAC PDUs aregenerated, the UE (e.g., the PHY) may use a number of layers and/or aprecoder, as indicated by the DCI for two codewords, to perform the ULtransmission (e.g., the number of layers and/or the precoder (e.g.,TPMI) may be determined based on and/or in accordance with informationof the two codeword column of Table 1 if the two MAC PDUs are generatedfor the TTI). Alternatively and/or additionally, if the two MAC PDUs aregenerated (for the TTI, for example) and the DCI indicates that twocodewords are enabled, the UE may determine the number of layers and/orthe precoder based on the indication of the DCI that two codewords areenabled (rather than the UE determining the number of layers and/or theprecoder based on an assumption that merely one codeword is enabled, forexample).

The network may need to attempt (and/or the network may be configured toperform) multiple decoding techniques and/or multiple decodinghypotheses (e.g., different decoding techniques and/or differentdecoding hypotheses) to decode an UL transmission by the UE because thenetwork may not know a number of transport blocks used for the ULtransmission, a number of layers used for the UL transmission and/or aprecoder used for the UL transmission. The network may not know thenumber of transport blocks, the number of layers and/or the precoderbecause the network may not know whether the UE generates one MAC PDUfor the UL transmission or two MAC PDUs for the UL transmission (whichmay be related to buffer status of the UE, for example). The network mayneed to (and/or the network may be configured to) blind decode themultiple decoding hypotheses and/or the multiple decoding techniques.For example, the network may decode the UL transmission with ahypothesis that two MAC PDUs are generated for the UL transmissionand/or the network may decode the UL transmission with a hypothesis thatone MAC PDU is generated for the UL transmission.

In some examples, the UE (e.g., the PHY) performs UL transmission forone MAC PDU. For example, the UE (e.g., the PHY) may perform ULtransmission for one MAC PDU if one MAC PDU is generated (by the UE,such as by a MAC of the UE, for example). The UE (e.g., the PHY) may notperform UL transmission for a second MAC PDU not generated by the UE(e.g., the MAC). The UE (e.g., the PHY) may perform UL transmission withtwo codewords (and/or two transport blocks). A first codeword of the twocodewords (and/or a first transport block of the two transport blocks)may be used to carry a MAC PDU (e.g., a generated MAC PDU). A secondcodeword of the two codewords (and/or a second transport block of thetwo transport blocks) may be used to carry a set of bits. The set ofbits may be randomly generated. The set of bits may have specific valuesand/or predefined values (e.g., the set of bits may comprise at leastone of all 0's, all 1's, 0101, etc.). The set of bits may be paddingbits or dummy bits. The set of bits may be generated by PHY of the UE.The set of bits may not be received from the MAC. In some examples, thefirst codeword of the two codewords (and/or the first transport block ofthe two transport blocks) may comprise data from UE. The second codewordof the two codewords (and/or the second transport block of the twotransport blocks) may not comprise data from UE. The second codeword ofthe two codewords (and/or the second transport block of the twotransport blocks) may be a special codeword (and/or a special transportblock). Alternatively and/or additionally, the second codeword of thetwo codewords (and/or the second transport block of the two transportblocks) may be a predefined codeword (and/or a predefined transportblock). Alternatively and/or additionally, the second codeword of thetwo codewords (and/or the second transport block of the two transportblocks) may be a dummy codeword (and/or a dummy transport block).Alternatively and/or additionally, the second codeword of the twocodewords (and/or the second transport block of the two transportblocks) may be filled with pre-generated, pre-known and/or randominformation.

In some examples, the UE may be configured for UL spatial multiplexingby the network. The UE may receive UL grants (e.g., two UL grants)dynamically on a PDCCH. In some examples, the UL grants are for spatialmultiplexing transmission. One or more actions, techniques and/oroperations provided herein performed by the UE may be performed by theUE, a MAC of the UE, a PHY of the UE, a HARQ entity of the UE, aMultiplexing and assembly entity of the UE, or a HARQ process of the UE(e.g., the UE may refer to at least one of the UE, the MAC, the PHY, theHARQ entity, the Multiplexing and assembly entity, the HARQ process,etc.).

The UE may be a LTE device. Alternatively and/or additionally, the UEmay be a NR device.

The network may be a base station. Alternatively and/or additionally,the network may be an access point. Alternatively and/or additionally,the network may be an eNB. Alternatively and/or additionally, thenetwork may be a gNB. Network, network node, base station, access point,eNB, and/or gNB may be used interchangeably throughout the presentdisclosure.

One, some and/or all of the foregoing techniques and/or embodiments canbe formed to a new embodiment.

In some examples, embodiments disclosed herein may be implementedindependently and/or separately. Alternatively and/or additionally, acombination of embodiments described herein may be implemented.Alternatively and/or additionally, a combination of embodimentsdescribed herein may be implemented concurrently and/or simultaneously.

Various techniques, embodiments, methods and/or alternatives of thepresent disclosure may be performed independently and/or separately fromone another. Alternatively and/or additionally, various techniques,embodiments, methods and/or alternatives of the present disclosure maybe combined and/or implemented using a single system. Alternativelyand/or additionally, various techniques, embodiments, methods and/oralternatives of the present disclosure may be implemented concurrentlyand/or simultaneously.

FIG. 6 is a flow chart 600 according to one exemplary embodiment fromthe perspective of a network. In step 605, the network transmits one ormore configurations to a UE. In step 610, the network is not allowed totransmit a first configuration of UL skipping to the UE and enable ULtransmission with two transport blocks for the UE.

In one embodiment, enabling UL transmission with two transport blockscorresponds to transmitting, to the UE, a second configuration of ULspatial multiplexing.

In one embodiment, the network schedules UL transmission for a TTI tothe UE.

In one embodiment, the UE is configured with the first configuration orthe second configuration (e.g., the UE is not concurrently and/orsimultaneously configured with both the first configuration and thesecond configuration).

In one embodiment, enabling UL transmission with two transport blockscorresponds to indicating to and/or instructing, in a DCI, the UE toperform UL transmission with two transport blocks.

In one embodiment, when (and/or if and/or based on a determination that)the UE is configured with both of the first configuration and the secondconfiguration, the network indicates to and/or instructs the UE toperform UL transmission with one transport block.

In one embodiment, the network indicates to and/or instructs the UE toperform UL transmission with one transport block by indicating, in a DCI(transmitted to the UE, for example), that a second transport block(other than the one transport block) is disabled.

In one embodiment, the network indicates to and/or instructs the UE toperform UL transmission with one transport block by scheduling the UEwith a DCI format associated with a single antenna port.

In one embodiment, enabling UL transmission with two transport blockscorresponds to enabling UL spatial multiplexing (for the UE).

In one embodiment, when (and/or if and/or based on a determination that)the UE is configured with both of the first configuration and the secondconfiguration, the network indicates to and/or instructs the UE todisable UL spatial multiplexing or the network indicates to and/orinstructs the UE not to enable UL spatial multiplexing.

In one embodiment, the network indicates to and/or instructs the UE todisable UL spatial multiplexing by scheduling the UE with a DCI formatassociated with a single antenna port.

In one embodiment, the network indicates to and/or instructs the UE notto enable UL spatial multiplexing by scheduling the UE with a DCI formatassociated with a single antenna port.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of anetwork, the device 300 includes a program code 312 stored in the memory310. The CPU 308 may execute program code 312 to enable the network (i)to transmit one or more configurations to a UE, and (ii) to not beallowed to transmit a first configuration of UL skipping to the UE andenable UL transmission with two transport blocks for the UE.Furthermore, the CPU 308 can execute the program code 312 to performone, some and/or all of the above-described actions and steps and/orothers described herein.

FIG. 7 is a flow chart 700 according to one exemplary embodiment fromthe perspective of a UE. In step 705, the UE receives a configurationfor UL transmission from a network node. In step 710, the UE receives ULgrants at a TTI. In step 715, the UE determines whether to generate oneor more MAC PDUs associated with the TTI.

In one embodiment, the configuration comprises an UL spatialmultiplexing configuration and an UL transmission skippingconfiguration.

In one embodiment, the UE does not skip an UL transmission for ULspatial multiplexing (e.g., an UL transmission performed using ULspatial multiplexing).

In one embodiment, the UE does not skip an UL transmission for ULspatial multiplexing (e.g., an UL transmission performed using ULspatial multiplexing) when (and/or if and/or based on a determinationthat) a MAC PDU associated with the UL transmission does not compriseavailable data of the UE.

In one embodiment, the UE skips an UL transmission for UL spatialmultiplexing (e.g., an UL transmission performed using UL spatialmultiplexing) when (and/or if and/or based on a determination that) theUE does not have available data (associated with the TTI, for example).

In one embodiment, the UE does not skip an UL transmission for ULspatial multiplexing (e.g., an UL transmission performed using ULspatial multiplexing) when (and/or if and/or based on a determinationthat) the UE has less than a threshold amount of available data (for theTTI and/or the UL transmission, for example). In some examples, thethreshold amount of available data may correspond to an amount ofavailable data accommodated by an UL grant of the UL grants (e.g., twoUL grants). For example, the UE having less than the threshold amount ofavailable data may indicate that the UE does not have enough availabledata for the TTI and/or the two UL grants (e.g., merely one UL grant ofthe two UL grants may accommodate all the available data).

In one embodiment, the UE does not skip an UL transmission for ULspatial multiplexing (e.g., an UL transmission performed using ULspatial multiplexing) when (and/or if and/or based on a determinationthat) the UE does not have enough available data, such as when the UEhas less than the threshold amount of available data.

In one embodiment, the UE generates a padding MAC PDU (associated withthe TTI, for example) when (and/or if and/or based on a determinationthat) the UE does not have enough available data, such as when the UEhas less than the threshold amount of available data.

In one embodiment, the UE generates two MAC PDUs (associated with theTTI, for example) when (and/or if and/or based on a determination that)the UE does not have enough available data, such as when the UE has lessthan the threshold amount of available data.

In one embodiment, the UE generates two MAC PDUs (associated with theTTI, for example), wherein one of the two MAC PDUs does not compriseavailable data.

In one embodiment, the UE does not generate any MAC PDU (associated withthe TTI, for example) when (and/or if and/or based on a determinationthat) both of the two MAC PDUs does not comprise available data. Forexample, the UE may not generate any MAC PDU (associated with the TTI,for example) when (and/or if and/or based on a determination that) theUE does not have available data to be included in a MAC PDU (e.g., anyMAC PDU) for the TTI. Alternatively and/or additionally, the UE may notgenerate any MAC PDU (associated with the TTI, for example) when (and/orif and/or based on a determination that) generation of the two MAC PDUswould result in the two MAC PDUs not comprising available data of theUE.

In one embodiment, the UE separates (and/or splits) available data ofthe UE to the two MAC PDUs associated with the TTI.

In one embodiment, the UE separates (and/or splits) the available datato the two MAC PDUs associated with the TTI to avoid one of the MAC PDUsnot comprising any available data of the UE (and/or to ensure that bothMAC PDUs of the two MAC PDUs comprise available data of the UE).

In one embodiment, the UE ignores one or more UL skipping conditionsassociated with the UL skipping and/or the first configuration.

In one embodiment, the UE obtains a MAC PDU (associated with the TTI,for example) from a second HARQ process buffer. In some examples, thesecond HARQ process buffer may be associated with a second HARQ processother than a related HARQ process that is associated with and/orallocated to the TTI and/or a first UL grant for which the MAC PDU isgenerated, where the second HARQ process may be associated with and/orallocated to the TTI and/or a second UL grant for the TTI.

In one embodiment, the UE performs the UL transmission with twotransport blocks, wherein a first transport block (e.g., one transportblock) of the two transport blocks comprises a MAC PDU and a secondtransport block (e.g., one other transport block other than the firsttransport block) of the two transport blocks does not comprise a MACPDU.

In one embodiment, the second transport block is a special transportblock, a predefined transport block, a dummy transport block, atransport block with known information, and/or a transport block withrandom information.

In one embodiment, the UE performs the UL transmission with a singletransport block when (and/or if and/or based on a determination that)the UE has less than the threshold amount of available data (for the TTIand/or the UL transmission, for example).

In one embodiment, the UE performs the UL transmission with a singletransport block when (and/or if and/or based on a determination that)the UE does not have enough available data, such as when the UE has lessthan the threshold amount of available data.

In one embodiment, the single transport block comprises a generated MACPDU (e.g., a MAC PDU generated by the UE) for the UL transmission.

In one embodiment, the UE does not generate two MAC PDUs for the ULtransmission.

In one embodiment, the UE performs the UL transmission with a singletransport block when (and/or if and/or based on a determination that)the UE does not generate two MAC PDUs for the UL transmission.

In one embodiment, the UE skips UL transmission for UL spatialmultiplexing when (and/or if and/or based on a determination that) theUE does not have enough available data, such as when the UE has lessthan the threshold amount of available data.

In one embodiment, the UE does not generate any MAC PDUs (associatedwith the TTI, for example).

In one embodiment, the UE discards a first MAC PDU (e.g., one MAC PDU)when (and/or if and/or based on a determination that) a second MAC PDU(e.g., another MAC PDU, other than the first MAC PDU, of two MAC PDUs,for example) associated with the TTI is not obtained.

In one embodiment, the UE does not instruct and/or does not perform theUL transmission when (and/or if and/or based on a determination that) aMAC PDU associated with the TTI is not obtained (e.g., any MAC PDU ofMAC PDUs, such as two MAC PDUs, associated with the TTI is notobtained).

In one embodiment, the UE does not perform the UL transmissionassociated with the TTI when (and/or if and/or based on a determinationthat) any of the MAC PDUs (e.g., two MAC PDUs associated with the TTI)is not obtained.

In one embodiment, the UE instructs and/or performs the UL transmissionwhen (and/or if and/or based on a determination that) two MAC PDUsassociated with the TTI are obtained.

In one embodiment, the UE performs the UL transmission associated withthe TTI when (and/or if and/or based on a determination that) two MACPDUs (associated with the TTI, for example) are obtained.

In one embodiment, the TTI is a given TTI.

In one embodiment, a DCI scheduling the UL transmission indicates toand/or instructs the UE to perform the UL transmission with twotransport blocks.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE,the device 300 includes a program code 312 stored in the memory 310. TheCPU 308 may execute program code 312 to enable the UE (i) to receive aconfiguration for UL transmission from a network node, (ii) to receiveUL grants at a TTI, and (iii) to determine whether to generate one ormore MAC PDUs associated with the TTI. Furthermore, the CPU 308 canexecute the program code 312 to perform one, some and/or all of theabove-described actions and steps and/or others described herein.

With respect to FIGS. 6-7, in one embodiment, aperiodic CSI is notrequested for the TTI. For example, there is no aperiodic CSI requestedfor the TTI. Alternatively and/or additionally, the UE may not berequested to provide aperiodic CSI (e.g., an aperiodic CSI report) tothe network via the TTI. Alternatively and/or additionally, the networkmay not request the UE to provide aperiodic CSI (e.g., an aperiodic CSIreport) to the network via the TTI.

In one embodiment, the TTI is and/or comprises a subframe, a slot, asubslot, a sTTI, 2 symbols, 3 symbols, and/or 7 symbols (and/or adifferent number of symbols).

In one embodiment, the UL transmission is a PUSCH transmission.

In one embodiment, the UE is a LTE device, a NR device and/or a NR-lightdevice.

In one embodiment, the network is a base station, an access point, aneNB, and/or a gNB.

FIG. 8 is a flow chart 800 according to one exemplary embodiment fromthe perspective of a UE configured with UL spatial multiplexing and ULskipping. In step 805, the UE receives, from a base station, two ULgrants for a TTI. In step 810, the UE generates two MAC PDUs for theTTI, wherein a first MAC PDU (e.g., one MAC PDU) of the two MAC PDUs isable to accommodate first available data (e.g., all available data) ofthe UE. In step 815, the UE transmits the two MAC PDUs to the basestation.

In one embodiment, the first available data may correspond to UE dataand/or UL data of the UE. For example, the first available data of theUE may correspond to UE data of the

UE that is available for UL transmission (e.g., PUSCH transmission).Alternatively and/or additionally, the first available data of the UEmay correspond to UE data of the UE that is available for ULtransmission (e.g., PUSCH transmission) using the two UL grants and/orthe TTI. Alternatively and/or additionally, the first available data ofthe UE may correspond to UE data of the UE that is available for one ormore logical channels (e.g., all logical channels) of the UE. In someexamples, the first available data may comprise all available data ofthe UE. All available data of the UE may correspond to all UE data ofthe UE that is available for UL transmission (e.g., PUSCH transmission).Alternatively and/or additionally, all available data of the UE maycorrespond to all UE data of the UE that is available for ULtransmission (e.g., PUSCH transmission) using the two UL grants and/orthe TTI. Alternatively and/or additionally, all available data of the UEmay correspond to all UE data of the UE that is available for one ormore logical channels (e.g., all logical channels) of the UE.

In one embodiment, the first MAC PDU is able to accommodate the firstavailable data (e.g., all available data of the UE) if the firstavailable data (e.g., all available data of the UE) can be included inthe first MAC PDU. Alternatively and/or additionally, the first MAC PDUis able to accommodate the first available data (e.g., all availabledata of the UE) if a size of the first MAC PDU exceeds a size of thefirst available data (e.g., a size of all available data of the UE).Alternatively and/or additionally, the first MAC PDU is able toaccommodate the first available data (e.g., all available data of theUE) if an amount of available data that can be included in the first MACPDU is the same as or larger than an amount of data of the firstavailable data (e.g., an amount of data of all available data of theUE). Alternatively and/or additionally, the first MAC PDU is able toaccommodate the first available data (e.g., all available data of theUE) if a capacity of the first MAC PDU is the same as or larger than anamount of data of the first available data (e.g., an amount of data ofall available data of the UE).

In one embodiment, the UE configured with UL spatial multiplexingreceives up to two UL grants for one TTI. For example, the UE receivesup to two UL grants for a second TTI (and/or the UE receives the two ULgrants for the TTI) based on and/or due to the UE being configured withUL spatial multiplexing.

In one embodiment, when the UE is configured with UL spatialmultiplexing, the UE receives up to two UL grants for one TTI. Forexample, when the UE is configured with UL spatial multiplexing, the UEmay receive up to two UL grants for one TTI based on and/or due to theUE being configured with UL spatial multiplexing.

In one embodiment, the UE does not receive an UL grant, other than thetwo UL grants, for the TTI. For example, the UE may merely receive thetwo UL grants for the TTI (and/or the UE may not receive more UL grants,than the two UL grants, for the TTI).

In one embodiment, the UE configured with UL skipping does not generatea MAC PDU for a dynamic UL grant when (and/or if and/or based on adetermination that) no data is available for a MAC PDU transmission(e.g., the UE has no available data for the MAC PDU transmission). Forexample, the UE may not generate the MAC PDU for the dynamic UL grantwhen no data is available for the MAC PDU transmission based on and/ordue to the UE being configured with UL skipping.

In one embodiment, when the UE is configured with UL skipping, the UEdoes not generate a MAC PDU for a dynamic UL grant if no data isavailable for MAC PDU transmission associated with the dynamic UL grant.For example, if the UE receives a dynamic UL grant and if the UE has nodata available for MAC PDU transmission associated with the dynamic ULgrant, the UE may not generate a MAC PDU for the dynamic UL grant basedon and/or due to the UE being configured with UL skipping.

In one embodiment, the UE receives a dynamic UL grant (other than thetwo UL grants, for example). The UE does not generate a MAC PDU for thedynamic UL grant when (and/or if and/or based on a determination that)the UE has no available data for a MAC PDU transmission associated withthe dynamic UL grant.

In one embodiment, the two UL grants are two dynamic UL grants for aHARQ entity.

In one embodiment, aperiodic CSI is not requested for the TTI. Forexample, there is no aperiodic CSI requested for the TTI. Alternativelyand/or additionally, the UE may not be requested to provide aperiodicCSI (e.g., an aperiodic CSI report) to the base station via the TTI.Alternatively and/or additionally, the base station may not request theUE to provide aperiodic CSI (e.g., an aperiodic CSI report) to the basestation via the TTI.

In one embodiment, one MAC PDU of the two MAC PDUs merely comprises aMAC CE, for a padding BSR or for a periodic BSR, with zero MAC SDUs(e.g., the MAC PDU and/or the MAC CE do not comprise any MAC SDUs). Forexample, the one MAC PDU may not comprise the first available data(and/or the one MAC PDU may not comprise any of the first availabledata).

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) the UE does not have availabledata to be included in a MAC PDU for the second TTI (e.g., the UE doesnot have available data to be included in a second set of two MAC PDUsfor the second TTI), and/or the UE merely has a MAC CE, for a paddingBSR or for a periodic BSR, with zero MAC SDUs, for inclusion in MAC PDUsfor the second TTI (e.g., the UE merely has a MAC CE, for a padding BSRor for a periodic BSR, with zero MAC SDUs, for inclusion in the secondset of two MAC PDUs for the second TTI).

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) both MAC PDUs of a second set oftwo MAC PDUs for the second TTI do not comprise available data of the UEand/or when (and/or if and/or based on a determination that) the secondset of two MAC PDUs for the second TTI merely comprise a MAC CE, for apadding BSR or for a periodic BSR, with zero MAC SDUs.

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) generation of a second set of twoMAC PDUs for the second TTI would result in the second set of two MACPDUs not comprising available data of the UE and/or when (and/or ifand/or based on a determination that) generation of the second set oftwo MAC PDUs for the second TTI would result in the second set of twoMAC PDUs merely comprising a MAC CE, for a padding BSR or for a periodicBSR, with zero MAC SDUs.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UEconfigured with UL spatial multiplexing and UL skipping, the device 300includes a program code 312 stored in the memory 310. The CPU 308 mayexecute program code 312 to enable the UE (i) to receive, from a basestation, two UL grants for a TTI, (ii) to generate two MAC PDUs for theTTI, wherein a first MAC PDU (e.g., one MAC PDU) of the two MAC PDUs isable to accommodate first available data (e.g., all available data) ofthe UE, and (iii) to transmit the two MAC PDUs to the base station.Furthermore, the CPU 308 can execute the program code 312 to performone, some and/or all of the above-described actions and steps and/orothers described herein.

FIG. 9 is a flow chart 900 according to one exemplary embodiment fromthe perspective of a UE configured with UL spatial multiplexing and ULskipping. In step 905, the UE receives, from a base station, two ULgrants for a TTI. In step 910, the UE generates two MAC PDUs for theTTI, wherein a first MAC PDU (e.g., one MAC PDU) of the two MAC PDUsmerely comprises a first MAC CE, for a first padding BSR or a firstperiodic BSR, with zero MAC SDUs (e.g., the first MAC PDU and/or thefirst MAC CE do not comprise any MAC SDUs) and a second MAC PDU (e.g.,one MAC PDU other than the first MAC PDU) of the two MAC PDUs comprisesfirst available data of the UE and/or a MAC SDU. In step 915, the UEtransmits the two MAC PDUs to the base station.

In one embodiment, the first available data may correspond to UE dataand/or UL data of the UE. For example, the first available data of theUE may correspond to UE data of the UE that is available for ULtransmission (e.g., PUSCH transmission). Alternatively and/oradditionally, the first available data of the UE may correspond to UEdata of the UE that is available for UL transmission (e.g., PUSCHtransmission) using the two UL grants and/or the TTI. Alternativelyand/or additionally, the first available data of the UE may correspondto UE data of the UE that is available for one or more logical channels(e.g., all logical channels) of the UE.

In one embodiment, the UE configured with UL spatial multiplexingreceives up to two UL grants for one TTI. For example, the UE receivesup to two UL grants for a second TTI (and/or the UE receives the two ULgrants for the TTI) based on and/or due to the UE being configured withUL spatial multiplexing.

In one embodiment, when the UE is configured with UL spatialmultiplexing, the UE receives up to two UL grants for one TTI. Forexample, when the UE is configured with UL spatial multiplexing, the UEmay receive up to two UL grants for one TTI based on and/or due to theUE being configured with UL spatial multiplexing.

In one embodiment, the UE does not receive an UL grant, other than thetwo UL grants, for the TTI. For example, the UE may merely receive thetwo UL grants for the TTI (and/or the UE may not receive more UL grantsthan the two UL grants for the TTI).

In one embodiment, the UE configured with UL skipping does not generatea MAC PDU for a dynamic UL grant when (and/or if and/or based on adetermination that) no data is available for a MAC PDU transmission(e.g., the UE has no available data for the MAC PDU transmission). Forexample, the UE may not generate the MAC PDU for the dynamic UL grantwhen no data is available for the MAC PDU transmission based on and/ordue to the UE being configured with UL skipping.

In one embodiment, when the UE is configured with UL skipping, the UEdoes not generate a MAC PDU for a dynamic UL grant if no data isavailable for MAC PDU transmission associated with the dynamic UL grant.For example, if the UE receives a dynamic UL grant and if the UE has nodata available for MAC PDU transmission associated with the dynamic ULgrant, the UE may not generate a MAC PDU for the dynamic UL grant basedon and/or due to the UE being configured with UL skipping.

In one embodiment, the UE receives a dynamic UL grant (other than thetwo UL grants, for example). The UE does not generate a MAC PDU for thedynamic UL grant when (and/or if and/or based on a determination that)the UE has no available data for a MAC PDU transmission associated withthe dynamic UL grant.

In one embodiment, the two UL grants are two dynamic UL grants for aHARQ entity.

In one embodiment, aperiodic CSI is not requested for the TTI. Forexample, there is no aperiodic CSI requested for the TTI. Alternativelyand/or additionally, the UE may not be requested to provide aperiodicCSI (e.g., an aperiodic CSI report) to the base station via the TTI.Alternatively and/or additionally, the base station may not request theUE to provide aperiodic CSI (e.g., an aperiodic CSI report) to the basestation via the TTI.

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) the UE does not have availabledata to be included in a MAC PDU for the second TTI (e.g., the UE doesnot have available data to be included in a second set of two MAC PDUsfor the second TTI), and/or the UE merely has a second MAC CE, for asecond padding BSR or for a second periodic BSR, with zero MAC SDUs, forinclusion in MAC PDUs for the second TTI (e.g., the UE merely has asecond MAC CE, for a second padding BSR or for a second periodic BSR,with zero MAC SDUs, for inclusion in the second set of two MAC PDUs forthe second TTI).

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) both MAC PDUs of a second set oftwo MAC PDUs for the second TTI do not comprise available data of the UEand/or when (and/or if and/or based on a determination that) the secondset of two MAC PDUs for the second TTI merely comprise a second MAC CE,for a second padding BSR or for a second periodic BSR, with zero MACSDUs.

In one embodiment, the UE receives, from the base station (or adifferent base station), a second set of two UL grants for a second TTI.The UE does not generate any MAC PDU for the second TTI when (and/or ifand/or based on a determination that) generation of a second set of twoMAC PDUs for the second TTI would result in the second set of two MACPDUs not comprising available data of the UE and/or when (and/or ifand/or based on a determination that) generation of the second set oftwo MAC PDUs for the second TTI would result in the second set of twoMAC PDUs merely comprising a second MAC CE, for a second padding BSR orfor a second periodic BSR, with zero MAC SDUs.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UEconfigured with UL spatial multiplexing and UL skipping, the device 300includes a program code 312 stored in the memory 310. The CPU 308 mayexecute program code 312 to enable the UE (i) to receive, from a basestation, two UL grants for a TTI, (ii) to generate, for the TTI, two MACPDUs, wherein a first MAC PDU (e.g., one MAC PDU) of the two MAC PDUsmerely comprises a first MAC CE, for a first padding BSR or a firstperiodic BSR, with zero MAC SDUs and a second MAC PDU (e.g., one MAC PDUother than the first MAC PDU) of the two MAC PDUs comprises firstavailable data of the UE and/or a MAC SDU, and (iii) to transmit the twoMAC PDUs to the base station. Furthermore, the CPU 308 can execute theprogram code 312 to perform one, some and/or all of the above-describedactions and steps and/or others described herein.

A communication device (e.g., a UE, a base station, a network node,etc.) may be provided, wherein the communication device may comprise acontrol circuit, a processor installed in the control circuit and/or amemory installed in the control circuit and coupled to the processor.The processor may be configured to execute a program code stored in thememory to perform method steps illustrated in FIGS. 6-9. Furthermore,the processor may execute the program code to perform one, some and/orall of the above-described actions and steps and/or others describedherein.

A computer-readable medium may be provided. The computer-readable mediummay be a non-transitory computer-readable medium. The computer-readablemedium may comprise a flash memory device, a hard disk drive, a disc(e.g., a magnetic disc and/or an optical disc, such as at least one of adigital versatile disc (DVD), a compact disc (CD), etc.), and/or amemory semiconductor, such as at least one of static random accessmemory (SRAM), dynamic random access memory (DRAM), synchronous dynamicrandom access memory (SDRAM), etc. The computer-readable medium maycomprise processor-executable instructions, that when executed causeperformance of one, some and/or all method steps illustrated in FIGS.6-9, and/or one, some and/or all of the above-described actions andsteps and/or others described herein.

It may be appreciated that applying one or more of the techniquespresented herein may result in one or more benefits including, but notlimited to, increased efficiency of communication between devices (e.g.,a UE and/or a network node). The increased efficiency may be a result ofenabling the UE to perform UL transmissions appropriately andefficiently, even when the UE is configured with UL spatial multiplexingand UL skipping. In an example, applying one or more of the techniquespresented herein enables the UE to generate and/or transmit two MAC PDUsfor a TTI even when a first MAC PDU of the two MAC PDUs merely comprisespadding (such as due to the second MAC PDU being able to accommodateavailable data of the UE), thus preventing a scenario in which the UE isunable to perform a transmission (such as due to a PHY of the UE beingunable to generate a 4 layer transmission with a single transportblock).

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based on designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Alternatively and/or additionally, in some aspects anysuitable computer-program product may comprise a computer-readablemedium comprising codes relating to one or more of the aspects of thedisclosure. In some aspects a computer program product may comprisepackaging materials.

While the disclosed subject matter has been described in connection withvarious aspects, it will be understood that the disclosed subject matteris capable of further modifications. This application is intended tocover any variations, uses or adaptation of the disclosed subject matterfollowing, in general, the principles of the disclosed subject matter,and including such departures from the present disclosure as come withinthe known and customary practice within the art to which the disclosedsubject matter pertains.

1. A method of a User Equipment (UE) configured with uplink (UL) spatialmultiplexing and UL skipping, the method comprising: receiving, from abase station, two UL grants for a Transmission Time Interval (TTI);generating two Medium Access Control (MAC) Protocol Data Units (PDUs)for the TTI, wherein a first MAC PDU of the two MAC PDUs is able toaccommodate all available data of the UE; and transmitting the two MACPDUs to the base station.
 2. The method of claim 1, wherein: when the UEis configured with UL spatial multiplexing, the UE receives up to two ULgrants for one TTI.
 3. The method of claim 1, wherein: when the UE isconfigured with UL skipping, the UE does not generate a MAC PDU for adynamic UL grant if no data is available for MAC PDU transmissionassociated with the dynamic UL grant.
 4. The method of claim 1, wherein:the two UL grants are two dynamic UL grants for a Hybrid AutomaticRepeat Request (HARM) entity.
 5. The method of claim 1, wherein:aperiodic Channel State Information (CSI) is not requested for the TTI.6. The method of claim 1, wherein: one of the two MAC PDUs merelycomprises a MAC Control Element (CE), for a padding Buffer Status Report(BSR) or for a periodic BSR, with zero MAC Service Data Units (SDUs). 7.The method of claim 1, comprising: receiving, from the base station, asecond set of two UL grants for a second TTI; and not generating any MACPDU for the second TTI based on a determination that at least one of:the UE does not have available data to be included in a MAC PDU for thesecond TTI; or the UE merely has a MAC Control Element (CE), for apadding Buffer Status Report (BSR) or for a periodic BSR, with zero MACService Data Units (SDUs), for inclusion in MAC PDUs for the second TTI.8. A method of a User Equipment (UE) configured with uplink (UL) spatialmultiplexing and UL skipping, the method comprising: receiving, from abase station, two UL grants for a Transmission Time Interval (TTI);generating two Medium Access Control (MAC) Protocol Data Units (PDUs)for the TTI, wherein: a first MAC PDU of the two MAC PDUs merelycomprises a first MAC Control Element (CE), for a first padding BufferStatus Report (BSR) or for a first periodic BSR, with zero MAC ServiceData Units (SDUs); and a second MAC PDU of the two MAC PDUs comprises atleast one of available data of the UE or a MAC SDU; and transmitting thetwo MAC PDUs to the base station.
 9. The method of claim 8, wherein:when the UE is configured with UL spatial multiplexing, the UE receivesup to two UL grants for one TTI.
 10. The method of claim 8, wherein:when the UE is configured with UL skipping, the UE does not generate aMAC PDU for a dynamic UL grant if no data is available for MAC PDUtransmission associated with the dynamic UL grant.
 11. The method ofclaim 8, wherein: the two UL grants are two dynamic UL grants for aHybrid Automatic Repeat Request (HARM) entity.
 12. The method of claim8, wherein: aperiodic Channel State Information (CSI) is not requestedfor the TTI.
 13. The method of claim 8, comprising: receiving, from thebase station, a second set of two UL grants for a second TTI; and notgenerating any MAC PDU for the second TTI based on a determination thatat least one of: the UE does not have available data to be included in aMAC PDU for the second TTI; or the UE merely has a second MAC CE, for asecond padding BSR or for a second periodic BSR, with zero MAC ServiceData Units (SDUs), for inclusion in MAC PDUs for the second TTI.
 14. AUser Equipment (UE) configured with uplink (UL) spatial multiplexing andUL skipping, the UE comprising: a control circuit; a processor installedin the control circuit; and a memory installed in the control circuitand operatively coupled to the processor, wherein the processor isconfigured to execute a program code stored in the memory to performoperations, the operations comprising: receiving, from a base station,two UL grants for a Transmission Time Interval (TTI); generating twoMedium Access Control (MAC) Protocol Data Units (PDUs) for the TTI,wherein a first MAC PDU of the two MAC PDUs is able to accommodate allavailable data of the UE; and transmitting the two MAC PDUs to the basestation.
 15. The UE of claim 14, wherein: when the UE is configured withUL spatial multiplexing, the UE receives up to two UL grants for oneTTI.
 16. The UE of claim 14, wherein: when the UE is configured with ULskipping, the UE does not generate a MAC PDU for a dynamic UL grant ifno data is available for the MAC PDU transmission associated with thedynamic UL grant.
 17. The UE of claim 14, wherein: the two UL grants aretwo dynamic UL grants for a Hybrid Automatic Repeat Request (HARM)entity.
 18. The UE of claim 14, wherein: aperiodic Channel StateInformation (CSI) is not requested for the TTI.
 19. The UE of claim 14,wherein: one of the two MAC PDUs merely comprises a MAC Control Element(CE), for a padding Buffer Status Report (BSR) or for a periodic BSR,with zero MAC Service Data Units (SDUs).
 20. The UE of claim 14, theoperations comprising: receiving, from the base station, a second set oftwo UL grants for a second TTI; and not generating any MAC PDU for thesecond TTI based on a determination that at least one of: the UE doesnot have available data to be included in a MAC PDU for the second TTI;or the UE merely has a MAC Control Element (CE), for a padding BufferStatus Report (BSR) or for a periodic BSR, with zero MAC Service DataUnits (SDUs), for inclusion in MAC PDUs for the second TTI.